Drugs are a problem that requires constant vigilance.需要对毒品问题长期保持警惕。Never relax your vigilance while you live in peace.你们要居安思危.Constant vigilance is necessary in order to avoid accidents.为了避免意外事故,必须经常保持警惕....
我们一家的开销每月共计四百元.The monthly expenditure of our family is four hundred dollars altogether.这张账单共计500美元.The bill amounts to $ 500.费用共计50美元.The expenses foot up to 50 dollars....