螺栓孔孔壁表面粗糙使用（）检验。
A.游标卡尺
B.卡尺
C.螺旋测微器
D.钢尺
参考答案：A
Among the subjects we study at school, I think English is ____________.
A．much difficult
B．interesting
C．more difficult
D．the most interesting
怎样搞好农业技术推广工作？
