我国对资本主义工商业社会主义改造实行的政策是（）。
A、加工订货
B、公私合营
C、赎买
D、没收
参考答案：C
Do not disturb me. I ________ letters all morning and have written ten so far. [ ]
A. write
B. have been writing
C. have written
D. was writing
梯形螺纹车刀的最大刀头宽度计算公式为：W=0.536P-0.366ac(其中P为螺距，ac为牙顶与牙底间的间隙)。( )
