选用since或for填空1.We have learned five lessons ____ the beginning of this term.2.Mrs Liao has been in hospital ____ last week.3.I have stayed at my aunt's ____ two weeks.4.He has studied very hard ____ he came to our school.5.We've been waiting ____ 20 minutes.

1.We have learned five lessons __since__ the beginning of this term.
2.Mrs Liao has been in hospital _since___ last week.
3.I have stayed at my aunt's _for___ two weeks.
4.He has studied very hard _since___ he came to our school.
5.We've been waiting __for__ 20 minutes.

1. since
2. since
3. for
4. since
5. for
for + 时间段
since + 时间点 / 或跟句子

1，since
2,since
3,for
4,since
5,for

1.sicnce，完成时
2.since，同上
3.for，一般过去时
4.since，完成时
5.for，一般过去时

1.since
2.since
3.for
4.since
5.for