汽油吹管火焰分为多层(带)，宜用于熔化合金的是
A．未完全燃烧带B．燃烧带C．还原带D．氧化带E．黄色带
参考答案：C
小医生，下列各句均有一处错误，请找出并改正。
1. We hear the twins are going to buy a present to their parents.
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2. You are the best teacher of all. Thank you to teach us so well.
3.people never use Mr, Mrs or Miss front their first names.
4.-Would you like to go swimming this Sunday?
-What a good idea! I'm glad.
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5.Next class we won't talk to anything about England.
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什么叫工作接地？什么叫重复接地？
