题目

— How did the boss pay you? — As a rule, we were paid ________. A. by the hour               B. by hour                      C. by an hour              D. by hours 答案：A夏天，荷叶上两滴小水珠靠近时，能自动结合成一滴较大的水珠，这一事实说明分子间存在着_________.满池荷花芳香扑鼻，该现象说明_________.