句型转换。

1.You can take a bus to the centre of Nanjing. (同义句转换)

   You can _____ the centre of Nanjing _____.

2. Why not visit the Great Wall in the summer holidays? (同义句转换)

   _____ you _____ the Great Wall in the summer holidays?

3.There is one tin of dog food in the fridge. (对划线部分提问)

   _____ of dog food are there in the fridge?

4.Miss Wang is a worker. (对划线部分提问)

   _____ Miss Wang ____?

5. It's forty minutes away from the bookshop to the theatre.

   _____ it from the bookshop to the theatre?

关于PGP安全电子邮件协议的描述中，正确的是______。

A．数字签名采用MD5

B．压缩采用RAR

C．报文加密采用AES

D．支持报文分段