对于焊缝表面缺陷的检测，应优先采用（）。
A、X射线探伤
B、超声波探伤
C、磁粉探伤
D、渗透探伤
参考答案：C
When I return to my hometown, I will call on Mr White who taught me ten years ago. The underlined part
means ______. [ ]
A. get back
B. give back
C. give out
D. go away
简述弗洛尹德的心理性欲阶段理论。
