It's ________ a visit ______ Yunnan_______ three days.

It's ________ a visit ______ Yunnan_______ three days. It is hard for them ______ the work in three days.A finish B it's the first time you visit this city,________? three- day,three days,three days',three day's区别? ______ four plus three?It's seven 补全对话：A:What's your favourite ________?B:______.It's always s Som __________(visit) china for three days. It's time-______ ________(go)home. It's a bad habit to sleep ______ _______ ______ ________(开着灯 ________?It's a dictionary. 单项选择（ ）21.It isn’t ______ ring.It’s ________ eraser.A.an,an It has three a's in it.