Here are the suggested correct forms or tenses for the verbs in brackets:

1. My father prefers **to work** as a farmer rather than a blue-collar worker.
2. I can't help **worrying** about her traveling abroad on her own.
3. Rubber sandals **were worn** by Vietnamese soldiers during the Americans.
4. In 1988, I **went** back to Vietnam after 30 years.
5. It is kind of you **to report** to her what happened to her son last night.
6. The number of vehicles in Vietnam **increases** by 10 percent every year.
7. Don’t you mind **traveling** so far every day?
8. After the war, Vietnamese people focused on dealing with domestic matters.

If you have any more questions or need further assistance, feel free to ask!