1.-Thank you very much helping to repair my computer.
-That’s all right.Thanks your letter,I can come in time and repair it for you.
答案：for;to
2.I don’t know what happened-we just got cut .
答案：off
3. more and more forests destroyed,some animals are facing the danger of dying out.
答案：With
4.Paper made the fibers of that plant is as soft and light as silk.
答案：from
5.He tried to speed the car,but it was impossible,for it was too old and it could only run a speed of 30 km an hour.
答案：up;at
6.Teachers and students couldn’t agree the spring outing,but the headmaster agreed the plan.
答案：on;to
7.It’s nice to travel expenses paid by your employers.
答案：with
8.I will go to attend the meeting on condition that it clears tomorrow.
答案：up
9.Little by little I have found my neighbor great help to my work and study.
答案：of
10.Every summer those who want to visit the Great Wall come to Beijing great numbers.
答案：in