题目

There are ____ of students in the school, but only ____of them are girls. A. hundreds, two hundred   B. hundred ,two hundreds C. hundreds, two hundreds  答案：A李明骑自行车，34小时行了454千米，如果要求平均骑行1千米要多少小时，列式是（　　）A．34÷454B．454÷34C．34×454