大型储罐罐底焊缝的致密性,应采用()方法进行检查。
A.真空箱试验
B.氨气试验
C.充水试验
D.煤油渗漏试验
参考答案:A
A.220V 5A
B.220V 15A
C.220V 20A
D.220V 10A
Tom is _______university student and he majors _______management at college. [ ]
A. an, in
B. a, in
C. an, /
D. a, at