---Thanks for your help, but can you do me one more favor, please? --- _______, sir.What's it then? A.Just a minute B.It's very nice of you C.That's all right D.At your service 答案:D 解析: at your service 意思是“听候你的吩咐”。
作用于同一点的两个力,其大小分别是6 N和10 N,无论这两个共点力的方向如何改变,它们的合力大小不可能是
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A.小于6 N
B.等于10 N
C.等于16 N
D.等于18 N