Chia động từ trong ngoặc

1. It’s ten in the morning. Everyone (run) .............around the stadium?

2. On my way to work I generally (meet)......... many children who (go) ..........to school.

3. He (study) ..............hard when he (be) .............young.

4. When we were kids, we (not understand)..........the importance of choosing a career

5. I’m going to the post office (buy) …………………….some stamps.