题目

完型填空10 Doctors tell us that holidays are necessary(必需的).We must rest from 1 for a week or two weeks every year. “If it is possible(可能的)，”they say, “we must 2 our homes and go to another 3 of the country. We must go 4 for a holiday. Then after the holiday, we are 5 home fresh and strong(精力充沛) and ready for another 6 of work.”This seems(似乎) to be right for most adults(成年人) but not for 7 . Some people don't like to leave their homes to stay in strange(陌生的) 8 . For young children it is usually quite different. They don't li如图所示，一条宽45m的河流，河水以4m/s的速度流淌．一只船欲从上游A码头直线到达下游对岸的B码头，已知AB=75m，则船在静水中航行的最小速度为 A．5m/s B．2.4m/s C．3.2m/s D．3m/s