触点式电压调节器的缺点有（）。
A．触点振动频率慢
B．机械惯性和电磁惯性大
C．电压调节精度低
D．对无线电干扰大
参考答案：A, B, C, D
Film has a much shorter history, especially when such art forms as music andpainting. [ ]
A. having compared to
B. comparing to
C. compare to
D. compared to
舟状头畸形的颅缝闭合特点一般表现为（）
A.矢状缝、人字缝提早闭合
B.矢状缝、冠状缝提早闭合
C.冠状缝、人字缝提早闭合
D.矢状缝、顶颞缝提早闭合
E.偏侧颅缝提早闭合
