【单选题】【消耗次数：1】
Greater efforts to increase agricultural production must be made if food shortage ＿＿＿＿＿＿ avoided.
①
is to be
②
can be
③
has been
④
will be
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相关题目
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The new technology has been ( ) in the industrial production.
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utilized
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possessed
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elevated
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focused
【单选题】
This kind of digital camera is considered the best that has been made ( )in our country.
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so on
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so that
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so far
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so as
【单选题】
[] has been made clear to all of us, none of you are to come late to class from today on.
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It
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As
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What
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Which
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The prices of the agricultural products have been ____ steadily in the past few years.
①
risen
②
raised
③
arisen
④
aroused
【单选题】
He has been writing the essay the whole morning and he still ＿＿＿ .
①
has been
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does
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has
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【单选题】
After Whitneys idea was applied to automobile production, each part____________ had to be made by hand.
①
no more
②
no more than
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no less than
④
no longer
【判断题】
More efforts, as reported, ___will be made___in the years ahead to accelerate the supply-side structural reform.
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正确
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The disappearance of her paper has never been _____.
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counted for
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随机题目
【单选题】
二维随机变量<imgwidth="46"height="21"v:shapes="_x0000_i1113"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb08.files/image159.png">概率密度为<imgwidth="203"height="50"v:shapes="_x0000_i1114"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb08.files/image161.png">则常数<imgwidth="16"height="19"v:shapes="_x0000_i1115"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb08.files/image163.png">为（）
①
<imgwidth="37"height="19"v:shapes="_x0000_i1116"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb08.files/image165.png">
②
<imgwidth="42"height="41"v:shapes="_x0000_i1117"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb08.files/image167.png">
③
<imgwidth="40"height="19"v:shapes="_x0000_i1118"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb08.files/image169.png">
④
<imgwidth="39"height="19"v:shapes="_x0000_i1119"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb08.files/image171.png">
【单选题】
将两封信随机地投入4个邮筒中，则未向前两个邮筒中投信的概率为（）
①
<imgwidth="22"height="44"v:shapes="_x0000_i1225"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb06.files/image335.png">
②
<imgwidth="26"height="48"v:shapes="_x0000_i1226"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb06.files/image337.png">
③
<imgwidth="26"height="46"v:shapes="_x0000_i1227"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb06.files/image339.png">
④
<imgwidth="20"height="41"v:shapes="_x0000_i1228"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb06.files/image341.png">
【单选题】
已知方阵<imgwidth="126"height="84"v:shapes="_x0000_i1154"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds05.files/image145.png">相似于对角阵，则常数<imgwidth="30"height="16"v:shapes="_x0000_i1155"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds05.files/image147.png">（）
①
<imgwidth="14"height="20"v:shapes="_x0000_i1156"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds05.files/image149.png">
②
<imgwidth="10"height="18"v:shapes="_x0000_i1157"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds05.files/image151.png">
③
<imgwidth="14"height="18"v:shapes="_x0000_i1158"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds05.files/image153.png">
④
<imgwidth="24"height="18"v:shapes="_x0000_i1159"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds05.files/image155.png">
【单选题】
设总体<imgwidth="86"height="22"v:shapes="_x0000_i1257"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb10.files/image373.png">，其中<imgwidth="35"height="22"v:shapes="_x0000_i1258"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb10.files/image375.png">已知，<imgwidth="86"height="22"v:shapes="_x0000_i1259"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb10.files/image377.png"><imgwidth="46"height="18"v:shapes="_x0000_i1260"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb10.files/image379.png">为来自总体<imgwidth="14"height="12"v:shapes="_x0000_i1261"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb10.files/image341.png">的样本，<imgwidth="14"height="18"v:shapes="_x0000_i1262"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb10.files/image382.png">为样本均值，<imgwidth="12"height="20"v:shapes="_x0000_i1263"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb10.files/image384.png">为样本方差，则下列统计量中服从<imgwidth="9"height="18"v:shapes="_x0000_i1264"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb10.files/image386.png">分布的是（）
①
<imgwidth="75"height="69"v:shapes="_x0000_i1265"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb10.files/image388.png">
②
<imgwidth="75"height="69"v:shapes="_x0000_i1266"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb10.files/image390.png">
③
<imgwidth="75"height="73"v:shapes="_x0000_i1267"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb10.files/image392.png">
④
<imgwidth="53"height="86"v:shapes="_x0000_i1268"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb10.files/image394.png">
【单选题】
设随机变量<imgwidth="110"height="25"v:shapes="_x0000_i1125"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb09.files/image167.png">为独立同分布序列，且<imgwidth="92"height="25"v:shapes="_x0000_i1126"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb09.files/image169.png">服从参数为<imgwidth="15"height="19"v:shapes="_x0000_i1127"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb09.files/image171.png">的指数分布，则下面式子中正确的是（）
①
<imgwidth="173"height="90"v:shapes="_x0000_i1128"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb09.files/image173.png">
②
<imgwidth="191"height="90"v:shapes="_x0000_i1129"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb09.files/image175.png">
③
<imgwidth="192"height="90"v:shapes="_x0000_i1130"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb09.files/image177.png">
④
<imgwidth="192"height="90"v:shapes="_x0000_i1131"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb09.files/image179.png">
【单选题】
<imgwidth="557"height="118"v:shapes="图片_x0020_13"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds01.files/image013.png">
①
<imgwidth="31"height="23"v:shapes="图片_x0020_14"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds01.files/image014.png">
②
<imgwidth="67"height="34"v:shapes="图片_x0020_15"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds01.files/image015.png">
③
<imgwidth="18"height="25"v:shapes="图片_x0020_16"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds01.files/image016.png">
④
<imgwidth="33"height="26"v:shapes="图片_x0020_17"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds01.files/image017.png">
【单选题】
设总体<imgwidth="63"height="20"v:shapes="_x0000_i1122"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image170.png">，则<imgwidth="12"height="14"v:shapes="_x0000_i1123"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image172.png">的矩估计和极大似然估计分别为（）
①
矩估计<imgwidth="40"height="22"v:shapes="_x0000_i1124"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image174.png">极大似然估计<imgwidth="35"height="22"v:shapes="_x0000_i1125"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image176.png">
②
矩估计<imgwidth="46"height="37"v:shapes="_x0000_i1126"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image178.png">极大似然估计<imgwidth="35"height="22"v:shapes="_x0000_i1127"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image176.png">
③
矩估计<imgwidth="46"height="37"v:shapes="_x0000_i1128"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image178.png">极大似然估计<imgwidth="37"height="37"v:shapes="_x0000_i1129"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image180.png">
④
矩估计<imgwidth="40"height="22"v:shapes="_x0000_i1130"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image174.png">极大似然估计<imgwidth="37"height="37"v:shapes="_x0000_i1131"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image180.png">
【单选题】
设随机事件A与B相互独立，<imgwidth="118"height="21"v:shapes="_x0000_i1058"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb06.files/image068.png">，则<imgwidth="77"height="21"v:shapes="_x0000_i1059"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb06.files/image070.png">（）
①
0.6
②
0.75
③
0.25
④
1
【单选题】
设<imgwidth="32"height="21"v:shapes="_x0000_i1056"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb07.files/image046.png">为两个随机事件，且<imgwidth="73"height="21"v:shapes="_x0000_i1057"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb07.files/image048.png">，则<imgwidth="80"height="21"v:shapes="_x0000_i1058"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb07.files/image050.png">（）
①
<imgwidth="37"height="21"v:shapes="_x0000_i1059"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb07.files/image052.png">
②
<imgwidth="48"height="21"v:shapes="_x0000_i1060"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb07.files/image054.png">
③
<imgwidth="66"height="21"v:shapes="_x0000_i1061"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb07.files/image056.png">
④
1
【单选题】
随机变量X服从正态分布<imgwidth="64"height="25"v:shapes="_x0000_i1160"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb07.files/image113.png">，则随着<imgwidth="16"height="15"v:shapes="_x0000_i1161"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb07.files/image222.png">的增大，概率<imgwidth="103"height="27"v:shapes="_x0000_i1162"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb07.files/image224.png">（）
①
单调增大
②
单调减小
③
保持不变
④
增减不定