干砌片石片石中部厚度不少于()cm。
A.10
B.15
C.20
D.25
参考答案:B
Schools across China are expected to hire 50000 college graduates this year as short-term
teachers , ________ reduce unemployment pressures. [ ]
A. help
B. to have helped
C. to help
D. having helped
矩形分幅的编号方法有西南角坐标编号法、()、行列编号法。