Part 4. Each sentence has ONE mistake. Find the mistakes and correct them
 1. If you go on littering, the environment will become seriously pollution.
2. My counsin has been in the army for he was eighteen.
3. She was tired. However, she took a rest before continuing the work
 4. Some designers has taken inspiration from Vietnam's ethnic minorities.
5. I haven't seen my grandparents since a quarter of a year.