4

Here are the corrected sentences for Task 3:

1. I am going to visit my grandparents next weekend.

2. By the time you arrive, I will have finished my homework.

3. She is meeting her boss at 10 a.m. tomorrow. It's already arranged.

4. The plane will leave at 8 p.m. tonight.

5. They will have been working here for 10 years by next month.