Ответ:
- Frank has decided to join/joining an environmental organization.
- Brian was looking forward to starting/to start his new job at the animal shelter.
- Volunteers from the area are spending this weekend to clean/cleaning up the local beach.
- People should use/to use eco-friendly cleaning products, which are safer for the environment.
- If you want to help the earthquake victims, you can donate/donate clothes and money at the local shelter.
Ответ: join, starting, clean, use, donate
Ты отлично справился с заданием! Правильный выбор формы глагола показывает твое хорошее понимание грамматики. Так держать!