题目

I hid the long black bag in the garage (车库) two days ago. Tonight, in the dark, I would finally take it away. If everything went OK, it would be done by morning. But I had to be sure no one, not even my wife, saw me.It was more difficult to get away from the party than I expected. I said that the children were tired and needed to get to bed. It was partly true. But the main reason for leaving was that I wanted to complete my plan.First I had to get the kids to sleep. That was never easy at any time and tonight it was even more difficult. The eldest one wanted to know why we left the party （附加题）有一块铜、锌合金，铜和锌的重量比为2：3，如果再加入锌6克，则新合金的重量为36克，求新合金中铜和锌的重量比．