结核菌素试验后正确的看结果的时间为()
A.24~48小时
B.48~72小时
C.3~7天
D.1~3周
E.20min
参考答案:B
— Excuse me, I am afraid your car is in way.
—I am so sorry.I will give way to your car right away.
A.a; a
B.a; the
C.the; a
D.the; /
轻质弹簧原长10cm,在它下面挂一个所受重力为4N的物体处于静止时,弹簧长12cm,则错误的是( )
A.该弹簧的劲度系数k=200N/m
B.物体受到的合力大小为4N
C.弹簧受到的拉力大小为4N
D.物体受到的弹力大小为4N