A：should
B：ca
C：may
D：need
(____) These are all books about science.
(____) That's a good idea.
(____) Let's put them on this shelf.
(____) We can put them on Shelf B.
(____) Let's make a home library.
下列有关细胞生长、分裂、分化和生物体结构层次的叙述，正确的是（ ）
我想起那参天碧绿的白桦林，标直漂亮的白桦树在原野上呻吟；我看见奔流似的马群，听见蒙古狗深夜的嗥鸣和皮鞭滚落在山涧里的脆响；我想起红布似的高梁，金黄的豆粒，黑色的土地，红玉的脸宠，黑玉的眼睛，班斓的山雕，奔驰的鹿群，带着松香气味的煤块，带着赤色的足金……这时我听见故乡在招唤我。
