_______________ are you? I'm little Water Drop. [ ]
A. Where
B. When
C. Who
答案:C
I’m sorry you’ve been waiting so long , but it will be an hour David gets back .
A.before
B.since
C.till
D.after
下列哪种细胞只有细胞器,却没有细胞核()。
A.白细胞
B.血小板
C.红细胞
D.淋巴细胞