阵雨降自（），毛毛雨降自层云、碎层云、（）。
参考答案：对流云；雾
旅行社安排的参观景点，因景点原因不能游览，旅行社应退还景点门票、导游费，并赔偿退还（）的违约金。
A．费用100%
B．费用20%
C．实际费用20%
D．费用10%
John spent most of his time practising speaking English in addition _____ his spare time. [ ]
A. of
B. to
C. for
D. into
