问题
单项选择题
对于机械性能要求不高和大尺寸、大截面的工件，可用正火代替（）处理。
A.退火
B.调质
C.淬火
D.表面热
答案
参考答案：B
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对于机械性能要求不高和大尺寸、大截面的工件，可用正火代替（）处理。
A.退火
B.调质
C.淬火
D.表面热
参考答案：B
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| Nowadays green food is popular. We know we need green food and good health, 1 not all people knew that years ago. When I was in Grade 8, my teacher asked us to 2 something about green food by ourselves. We didn't have any idea at first. Then our four-member group had a 3 and decided to do some research in a supermarket. Two of us wrote down the names of the 4 food on the shelves. The other two asked 5 some questions like "Do you know what green food is?" "How often do you 6 green food?" and so on. More than 30 customers 7 our questions! Later each group in our class wrote a research report 8 the topic and handed it in. Our teacher chose the 9 ones and put them up on the wall of the classroom. 10 was among them! We not only learned a lot about green food but also knew how to keep healthy. | |||
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