公安部门要求小型客车的驾驶员必须使用安全带，如图所示，这是为了防止高速行驶的汽车紧急刹车时由于_________ 而撞伤．
具有惯性
The Harry Potter books _____ pretty popular since they were published. [ ]
A. become
B. will become
C. have become
D. are becoming
单位定期账户存款方式分为无折转账和现金存款。
