题目内容：

once a day

优质解答

once a day:
每天一次
例句与用法:
1.I have to mop the kitchen floor at least once a day.
我每天至少要把厨房地板擦洗一次.
2.Put a plaster on the sore once a day.
把这膏药每日一次敷贴患处.