句型转换。

1.There are many cars and buses on the street. (改为一般疑问句)

2. She is reading a book. (就画线部分提问)

3. Jenny can fly a kite. (改为否定句)

4. He hurts his nose. (改为同义句) 

5. This is easy for me. (改为同义句)

一般离心泵的泵轴穿过泵壳处的密封有（）和机械密封。