1) Read these sentences and fill in the gaps with 'could', 'can', 'couldn't', 'can't'.
They start their work when they want.
2) Read these sentences and choose the correct variant.
1. He doesn't has to work in the evening
2. He doesn't have to work in the evening
1) They can start their work when they want
2) 2. He doesn't have to work in the evening