Fill each gap in the sentences with when or while.

1. Was it snowing _ __while_____ you went to bed last night?

$\longrightarrow$ dùng while

2. They had lunch ____while____ they were waiting for the plane.

$\longrightarrow$ dùng while

3. ___when__ she put new batteries in the toy, it started working again.

$\longrightarrow$ dùng when

4. __while___ I was walking home, I fell over and cut my knee.

$\longrightarrow$ dùng while 

5. Helen didn't say hello ___when_____ I saw her this morning.

$\longrightarrow$ dùng when

6. __when ___ you were out jogging, Frank brought your book back.

$\longrightarrow$ dùng when

7. Did everybody go home ___when_____ the concert finished?

$\longrightarrow$ dùng when

8. I read it ____while____ you were drying your hair.

$\longrightarrow$ dùng while

9. I was just getting into the bath ___when_____ the telephone rang.

$\longrightarrow$ dùng when 

10. ___while__ my father was reading the newspaper, I was watching TV.

$\longrightarrow$ dùng while