增温带中深度每增加100米，温度升高的度数称（）。
参考答案：地温梯度
They had their bad times but on the whole they were ______ happy. [ ]
A. rarely
B. merely
C. fairly
D. chiefly
现代物流是以（）为出发点的服务，强调一切以客户为中心。
A.市场开始
B.客户满意
C.成本效益
D.市场占有率
