The sign means _____.

— What have you been busy with these days?— I ______ that the speech contest has been brought forward, so I ______ for it. [ ]

Many people are __________ building a chemical factory（化工厂）near here . They are worrying about the possible pollution .

I have never been to the Great wall. —If you have an opportunity _______ there, you must take it.

I was really anxious about you. You _____ __ home without a word.