从一批产品中随机抽两次,每次抽1件。以A表示事件“两次都抽得正品”,B表示事件“至少抽得一件次品”,则下列关系式中,正确的是()
①
<imgwidth="46"height="17"v:shapes="_x0000_i1077"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb06.files/image102.png">
②
<imgwidth="46"height="17"v:shapes="_x0000_i1078"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb06.files/image104.png">
③
<imgwidth="42"height="17"v:shapes="_x0000_i1079"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb06.files/image106.png">
④
<imgwidth="42"height="20"v:shapes="_x0000_i1080"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb06.files/image108.png">