先天性聋多为（）。
A.轻度聋
B.中度聋
C.中重度聋
D.重度聋
E.极度聋
参考答案：D, E
A ______ and ______ has been bought for you. Which is wrong? [ ]
A. gold watch, chain
B. knife, fork
C. desk, chair
D. pen, pencil
设计实验：证明KClO3中含有氯元素：
①______；②______；③______．
