1. When September comes, it starts to get cooler.

当…的时候

2. We also go back to school as soon as the May Day holiday is over.

一…就…

3. While we’re staying with them, we’re going to spend a few days in Qingdao.

当…的时候

4. We only have a few weeks before the start of the summer holiday.

在…之前

5. Let’s enjoy ourselves until we go back to school.

直到…

6. She's changed much since she got that job.

自从