下列物品所用的主要材料属于天然纤维的是[ ]
A.合成橡胶
B.尼龙绳
C.棉布衬衣
D.不锈钢杯
答案:C
We can hardly believe that an intelligent person like Daniel ________ be asking such a silly question.
A.should
B.might
C.must
D.could
GB252中规定0号柴油冷滤点不高于()。