用所给词的适当形式填空。

1.  How much______ (be) the red hat?

2.  My mother ______ (want) to go shopping.

3.  Do you want______ (help) them?

4.  I have three______ (pair) of shoes.

5.  They sell school______ (thing).

内质网的分类和在电镜下的结构。