We often go to the Children's Palace _____ Sunday. [ ]
A. on
B. at
C. in
D. for
答案:A
单项选择。
Can she ______ it ______ Mr Zhang? [ ]
A.gives, /
B.give, to
C.gives, to
D.give, /
20个小孢子母细胞能产生()个花粉粒,4个小孢子产生()个花粉粒。