根据要求转换句型。

1．There will be less pollution in the air in the future. (改为否定句) 

      There                             less pollution in the air in the future.

2．It's about 30 minutes' bus ride from here to Beibei. (对划线部分提问) 

                                 is it from here to Beibei?

3．My best friend Nancy has never been to the Great Wall. I haven't,either. (同义句)

      My best friend Nancy has never been to the Great Wall.                             I.

4．She has to work twelve hours every day. (变为一般疑问句) 

                   she              to work twelve hours every day?

5．我期待收到你的来信. 

      I am looking forward to                              you.

内存按字节编址，地址从90000H到CFFFFH，若用存储容量为16K×8bit的存储器芯片构成该内存，至少需要______片。

A．2
B．4
C．8
D．16