常见的自动变速器油泵有（）几种类型。
A.内啮合齿轮泵
B.摆线转子泵
C.叶片泵
D.柱塞泵
E.外啮合齿轮泵
参考答案：A, B, C
Parents and teachers should help teenagers control their use of computer games ______be controlled by themselves.
A．other than
B．better then
C．rather than
D．more than
请在图中，标出通电螺线管的电流方向和南、北极，以及小磁针的南、北极．
