（）锉削法是钳工对凸凹模腔精修加工的常用方法。
A.划线
B.压印
C.样板检查
参考答案：B
It is reported that China will not buy the Euro debt until some thorough research ______.
A．will be done
B．had been done
C．has been done
D．will have been done
从所给的四个选项中，选择最合适的一个填入问号处，使之旱现一定的规律性（）
A.选项A
B.选项B
C.选项C
D.选项D
