1 In the end I had no choice but to get a lift with a colleague (could).

-> In the end all I could do was to get a lift with a colleague.

2 By law, all rear-seat passengers are obliged to wear seat-belts (have).

-> By law, seat- belts have to be worn by all rear-seat passengers.

3 It's not neccessary for you to do the test.

-> You don't have to do the test.

4 Nobody can deny that she has a beautiful voice.

-> It can’t be denied that she has a beautiful voice.

1. In the end all I could do was to get a lift with a colleague.

2. By law, seat-belts have to be worn by all rear-seat passengers.

3. You don't need to do the test.

4. It can't be denied that she has a beautiful voice.