下面哪种裂纹通常是由于局部过热引起、且呈现为不规则的网状或分散的细线条状?()。
A.疲劳裂纹
B.磨削裂纹
C.弧坑裂纹
D.热影响区裂纹
参考答案:B
—How's Joy's skirt?
—Her skirt is more beautiful than _____. [ ]
A. her sister's and Kate
B. her sister and Kate
C. her sister and Kate's
D. her sister's and Kate's
下面关于函数依赖的叙述中,不正确的是
A.若X→Y,Y→Z,则X→Z
B.若X→y,且Y→CY,则X→Y,
C.若X→Y,X--Z,则X→YZ
D.若XY→Z,则X→Z,Y→Z