单项选择题
A moving object will not accelerate or decelerate （）a force is applied to it.
A.whether B.if C.unless D.till
单项选择题 When was your ship built? （）is a new oneShe was delivered to us by Bremen Shipyard only three months ago.
单项选择题 Every precaution must be taken to avoid （）.
单项选择题 It is obvious that the expansion of the water （）the increase of its temperature.
