句型转换。

1. This is his brother. (改为复数句子)

     ______ are their______ .

2. That girl is my sister. (改为一般疑问句)

     ______ that girl______ sister?

3. Those are my friends. (改为单数句子)

     ______ ______ my______.

4. They are English books. (改为单数句子)

     ______ is______ English______.

5. She is my grandmother. (改为否定旬)

    She______ my grandmother.

我司的核保政策规定，公众责任险、产品责任险的司法管辖权可扩展至世界范围，但是美、加除外，为什么？