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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 surpised, because I never ( to see) a grizzly bear.
4.The forest was full of rubbish. Somebody (to thow) 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.