千分尺使用中不要拧松后盖,否则零件可能改变,如果后盖松动,就要校对()。
A.零位
B平行
C.垂直
参考答案:A
The boy came to ____ life after the operation, although he was once ____ failure. [ ]
A. a; a
B. / ; a
C. a; /
D. /; /