焊接条件下的CCT曲线的形状，从根本上来说取决于（）
A.母材的成分
B.冷却速度
C.晶粒度
参考答案：A
按书写要求重写下列句子.
1. my name is tony smith and i speak english
__________________________________
2. i am betty rixon an my father is american
__________________________ _______
3. this is my father an he’s a manager
_______________________ ____
4. these are daming’s parents
_________________________
5. my mother is an english teacher in beijing
“十大礼貌用语”是什么？
