1. Mr and Mrs . smit are flying to Ha Noi now. (TRAVELLING)

=> Mr and Mrs. Smit are travelling to Ha Noi now.

2. Van had motorbike once , but now he doesn't any more. (USED)

=> Van used to have a motorbike once.

3. My fathar usually goes to work by car.(DRIVES)

=> My father usually drives to work.

4. This past of the city didn't have traffic jam. (USE)

=> This part of the city didn't use to have traffic jam.

5. I used to walk to school when I was young. (FOOT)

=> I used to go to school on foot when I was young.