边际进口倾向是指（）增加在（）增加中所占的比例。
参考答案：进口；国内生产总值
Was it because of the heavy snowstorm in Europe _____ the flight had to be put off? [ ]
A. which
B. so
C. why
D. that
疫区来货到达口岸时，货主或代理人必须向检验检疫机关申报并提供所需资料、单证，主要有：报验员证或驾驶员培训合格证。（）
