周期型行业的运动状态与经济周期呈负相关，既当经济处于上升时期，这些行业会收缩；当经济衰退时，这些行业会扩张。（）
参考答案：错
A．甲烷、乙烷属于烷烃
B．维生素属于糖类
C．油脂属于酯类
D．纤维素属于糖类
—The day after tomorrow is Christmas Eve. What will you send your grandpa _________ from here?
—I shall send a _________ to him.[ ]
A. close, postcard
B. far, postcards
C. close, postcards
D. far, postcard
