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.