【单选题】【消耗次数：1】
聚四氟乙烯膜缺点不包括
①
口腔软组织开裂造成膜暴露几率较高，可能导致感染
②
膜为疏水性的，操作较困难，需要机械固定
③
需要二次手术取出
④
屏障稳定性差
⑤
以上都是
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相关题目
【单选题】
聚四氟乙烯膜优点不包括
①
具备良好的生物相容性
②
具备不可降解性和生物学惰性
③
不吸收，屏障稳定性好
④
表面有50nm、特定孔隙，可以隔离成纤维细胞，孔的大小允许细胞及小血管长入，有利于血管源性细胞增殖
⑤
不需要二次手术取出
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“不粘锅”饮具是在金属锅的内壁上涂一薄层聚四氟乙烯制成，下列各项对聚四氟乙烯的叙述中正确的是( )。
①
聚四氟乙烯的化学性质很稳定，正常使用时不会发生化学变化
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聚四氟乙烯的分子内支链很多，且彼此缠绕，不会污染食物
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聚四氟乙烯在高温时容易燃烧
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在聚四氟乙烯的单体中不含有碳碳双键
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This is a big class, and ______ of the students are girls.
①
two third
②
second three
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two thirds
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two three
【单选题】
3.Iveread_______sportsnewsabouttheF1racetoday.
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two
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pieces
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two pieces
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two pieces of
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a two-month
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two months
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two-months
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two months
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two pair of shoes
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two pairs of shoe
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two pair of shoe
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two pairs of shoes
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a half and two hour
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two and a half hour
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two hour and a half
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two and a half hours
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—Whats one fourth and a half, do you know?—Yes, its ______.
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two sixths
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three fourths
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one three
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three sixths
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twentieth; one ?
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twenty; one
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twentieth; first
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twenty; first
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2.Thereare_______daysinayear.
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three hundred and sixty-five
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three hundred and sixty five
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three hundred sixty-five
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three hundreds and sixty- five
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Time is not enough for so much work. ______ people are needed, I think.
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Other two
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Only two
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Two more
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—How many people will come to Beijing for the Olympic Games in 2008?—Its hard to say. _______ people, I think.
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Million of
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Millions of
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Two millions of
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Two million of