Open the brackets and use the correct tense form.
1. Jane (to learn) a lot of things about animals by Friday.
2. The students (to prepare) for the trip by that time yesterday.
3. I was surprised, because I never (to see) a grizzly bear.
4. The forest was full of rubbish. Somebody (to throw) it.
5. When the students (to return) their friends (to go) away.
6. When we (to reach) the forest the travellers already (to camp).
7. The students (to solve) some ecological problems in the camp by Sunday.
Помогите! Заранее спасибо!