用65Mn钢做弹簧，淬火后应采用（）。
A、高温回火
B、低温回火
C、中温回火
参考答案：C
根据句意及汉语提示完成下列句子.
1. There is a _____ (干净的) park in front of the supermarket.
2. The shop is _____ (开着的) every day.
3. Bridge Street is a _____ (宁静的) street.
4. Your jacket is _____ (脏的). Please wash it.
5. There is a _____ (市场) near my _____ (房子).
试述温室和大棚设计的主要步骤。其主要作用是什么？
