伺服油缸式舵机遥控系统控制油泵常采用（）。A.齿轮泵 B.螺杆泵 C.叶片泵 D.柱
题型：单项选择题
问题：
伺服油缸式舵机遥控系统控制油泵常采用（）。
A.齿轮泵
B.螺杆泵
C.叶片泵
D.柱塞泵
题型：单项选择题
| 选择与句子相符的图片。 | |
| ( ) 1. The little boy phoned his friend last Monday. | A. |
| ( ) 2. Lingling had a fever last Sunday. | B. |
| ( ) 3. He listened to music yesterday. | C. |
| ( ) 4. Lily went for a bike ride yesterday. | D. |