能正确表示动物与其气体交换部位连线的是（ ）

A．蚯蚓—体壁

B．家鸽—肺和气囊

C．蝗虫—气门

D．鲨鱼—肺

句型转换。

l. Jenny was late for school yesterday.(改为一般疑问句)

2. He can work out the math problem.(改为否定句)

3. Let's play games together.(改为否定句)

4. They have lived here for many years.(就画线部分提问)

5. His brother usually goes to school by underground.(就画线部分提问)

6. I could swim when l was eight.(改为同义句)

    I could swim ______ eight.