控制洗地毯机的走向，应由()，保持()的速度为宜。
A. 左至右，40米/分
B. 上至下，50米/分
C. 右至左，30米分
D. 随意，20米/分
You hear on the radiotelephone the word“Securite”spoken three times.This indicates that ().
A message about the safety of navigation will follow
B. A message of an urgent nature about the safety of a ship will follow
C. The sender is in distress and requests immediate assistance
D. You should secure your radiotelephone
砂仁和豆蔻功效的共同点是
A. 安胎
B. 祛风
C. 燥湿
D. 止泻
储油箱内的油量应能满足发电机运行()的用量，油位显示应正常。
A. 2-6h
B. 5-6h
C. 3-8h
D. 2-5h
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