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问题
单项选择题
由两种或两种以上的物质生成（）物质的反应叫做化合反应。
A.另一种
B.另两种
C.另三种
D.另四种
答案
参考答案：
A
选择题
When I asked her what she did yesterday, she pretended ___ about it.
A. not to hear
B. not having heard
C. to not have heard
D. not to have heard
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判断题
传染的概念是人体同侵入的病原体相互作用、相互斗争的过程。
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