氧一乙炔焰堆焊时，熔深（）。
A.无特殊要求
B.越深越好
C.越浅越好
参考答案：C
—What did Lu Xun do after he gave up medicine?
—He devoted _____writing all his rest life. [ ]
A. him to
B. himself in
C. himself to
D. her in
吊笼每运行半月或停运（）月后启用时必须对吊笼进行全面检查。
A.1
B.2
C.3
D.4
