用所给代词的适当形式填空。

1. _____ is Chinese. (his)

2. This is Mark. _____book is here. (he)

3. That's Lisa. _____ pencil is old. (she)

4. _____ is my English teacher. (her)

5. Is that _____ backpack, Jones? (you)

下列哪些单位或组织不能作为保证人( )。

A．国家机关

B．儿童医院

C．海尔集团生产部

D．清华附中

E．青岛啤酒集团