chu vi hình tròn cũ là:

    18,84:20x100=94,2

1. I /write/you/bad situation/affect/lake/school

=> I'm writing to you about bad situation, which is affecting the lake near my school.

2.As you know/lake/school/be/beautiful

=> As you know, the lake near my school is very beautiful.

3.However/it/become/polluted

=> However, it has become polluted.

4.People/electricity/fish

=> People have used electricity to catch fish.

5.A lot/fish/die/float/water surface

=> A lot of fish died and floated on the water surface.

6.people/throw/rubbish/waste into/lake

=> People have thrown rubbish and waste into the lake

7. now/bad smell/affect/school children's health.

=> Now, bad smell is affecting my school children's health.

8.What/you/think/polluted air?

=> What do you think about this polluted air?

9. look forward to/hear/you/see/protection/environment/local authority

=> I am looking forward to hearing from you and seeing the protection of the environment from the local authority.

10.sincere/long

=> Sincerely, Long.

1.I would suggest/that you/tell/works/clean up/ beaches.

=> I would suggest that you must tell the workers to clean up the beaches.

2. I/ write/ you /because/beaches/our city/tremely dirty.

=> I am writing to you because the beaches in our city are extremely dirty.

3. They /full/litter/waste/dog dung /when/I /go/there/last week.

=> They were full of litter, waste and dog dung when I went there last week.

4. They /smell/unpleasant/that time/tourist/I/annoyed

=> They smelled unpleasant, at that time tourist an I were annoyed.

5.They /still/in a mess/this week.

=> They are still in a mess this week.

6.I look forward/receive/good response/you

=> I am looking forward to receiving a good response from you.