下列用电器中，不需要变阻器的是      （  ）

选出划线部分发音不同的一项

读下列大洲轮廓图，回答下列问题。

     Tom and Mike are good friends. They are good with children. They want to find jobs in summer vacation. This Friday Tom tells Mike that Sunson School Trip needs teachers to help with sports, music and computer. Mike is glad to know that.
    Tom can play basketball, volleyball, and he can swim. Mike can play the violin, the trumpet, the drums and the guitar, and he can swim,too. Tom and Mike like computers very much. Can they join Sunson School Trip?

_______ I walked into class, the teacher had started teaching already.