3. Complete the sentences with the correct form of the verbs in brackets. Use the past simple or past continuous. 1) I (walk) home when I (see) an accident. 2) While we (wait) for the bus, it (begin) to snow. 3) He (break) his leg while he (ski). 4) They (have) a picnic when it (start) to rain. 5) I (meet) an old friend while I (shop) in town.

1. I was walking home when I saw an accident.
2. While we were waiting for the bus, it began to snow.
3. He broke his leg while he was skiing.
4. They were having a picnic when it started to rain.
5. I met an old friend while I was shopping in town.

Past continuous gives the background action; past simple marks the event that happened during it.