构成毛细血管壁的细胞层数是( )
A:一层
B:二层
C:五层
D:十层
下面的哪些老鼠可以通过平移与灰色老鼠重合?把它们圈出来。
⑴____ A. sail B. may C. park
⑵____ A. girl B. turn C. tea
⑶____ A. warm B. car C. star
⑷____ A. but B. us C. use
⑸____ A. match B. fish C. short
Many ____ (visit) come to Kunming every year.