下列动物中不存在变态发育的一组是（ ）。

A．蜻蜓和苍蝇

B．蚊子和蜜蜂

C．青蛙和蟾蜍

D．鲫鱼和鸡

一I heard that you got an A in the chemistry exam．Well done!

一Thanks，I know that you     a good job as well．

A．shouId have done

B．need have done

C．must have done

D．could have done