如图所示,滑块A 受到沿斜向上方的拉力F作用,向右做匀速直线运动,则滑块受到的拉力与摩擦力的合力方向是
A.向上偏右
B.竖直向上
C.向上偏左
D.竖直向下
答案:B
I had neither a raincoat nor an umbrella. That's why I _____ wait until the rain stopped. [ ]
A. might
B. should
C. ought to
D. had to
以下哪项不是肝肾亏损型痛经的主证:()
A.经后一二日小腹隐痛
B.腰部酸胀
C.阴部空坠
D.经色黯淡
E.头晕耳鸣