— There's someone outside. Who it be ?— It must be Mary. She promised to come over at 8: 00.

We ____ a word unless she asks us ____.

Let’s clean the classroom, ＿＿＿＿＿＿＿? 

It’s said that there are plenty of hotels in that town. There ______ be any difficulty for you to find somewhere to stay.   

If I＿＿＿you, I＿＿＿＿more attention to English idioms and phrases.