28. All children’s shoes are now______________________to $20 a pair. a. reduced b. reused c. refilled d. recycled 29. ______________________is a mixture of decaying plants and vegetables that is added to soil to improve its quality. a. Compost b. Dung c. Trash d. Fertilizer 30. The sea and rivers are too______________________to sưim in. a. dirt b. dirty c. dirtily d. dirtiness 31. An astronaut would be killed if he or she ______________________by a piece of rubbish. a. was hit b. were hit c. was hitted d. were hitted 32. Milk bottles can be ______________________after being cleaned. a. collect b. thrown away c. broken d. reused 33. Teachers ought not to swear in front of the children. ______________________ (find the synonym) a. should not b. need not c. could not d. don’t have to 34. It is not always easy______________________good teaching materials in this field. a. find b. to find c. finding d. for finding 35. It is important ______________________students attend all the lectures. a. that b. in order to c. to d. 0