对于同种材料,其晶粒组织越大,加工表面粗糙度越大,所以常在加工前安排()处理,以获得均匀细密的晶粒组织。
A. 时效
B. 渗碳
C. 淬火
D. 调质
E. 正火
凡是通过极性键或氢键水化的基团,高温去水化作用一般较弱;而由离子基水化形成的水化膜,高温去水化作用相对较强。
A. 正确
B. 错误
There()a basketball match this afternoon.
A. is going to be
B. is going to have
C. is going to is
D. is going to ha