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?

too和food中的“oo”字母组合发音相同。

“水”严重制约着西北地区的发展，解决西北地区水源紧缺最经济、实用的办法是（    ）

①跨流域调水 ②人工降雨 ③大力开采地下水 ④建集雨节灌水窖

鉴别稀硫酸和浓硫酸既简单、又可靠的方法是（  ）

直线所得劣弧所对圆心角为    （   ）