（ ）8. A. bristle B. castle C. firstly D. whistle
（ ）9. A. physics B. recycle C. bye D. hydrogen
（ ）10. A. return B. Saturday C. surface D. murder
Exercise 12：
（ ）1. A. medicine B. bicycle C. medical D. certain
（ ）2. A. early B. research C. heard D. disappear
（ ）3. A. debt B. climb C. cabin D. comb
（ ）4. A. worked B. defended C. stressed D. finished
（ ）5. A. moves B. manages C. changes D. rises
（ ）6. A. extremely B. example C. experience D. extend
（ ）7. A. result B. thrust C. reduce D. trunk
（ ）8. A. powder B. own C. meadow D. follow
（ ）9. A. plain B. said C. main D. brain
（ ）10. A. chemistry B. stomach C. headache D. chest
Exercise 13：
（ ）1. A. unite B. union C. unfair D. universe
（ ）2. A. kilometer B. pretty C. complete D. scene
（ ）3. A. technical B. children C. satellite D. universe
（ ）4. A. chemist B. check C. children D. chicken
（ ）5. A. bread B. ready C. break D. weather
（ ）6. A wear B. earth C. search D. learn
（ ）7. A mountain B. shout C. mouth D. cough
（ ）8. A. any B. apple C. black D. thank
（ ）9. A. spell B. telephone C. she D. second
（ ）10. A. sew B. flew C. threw D. blew
Exercise 14：
（ ）1. A. now B. how C. down D. snow
（ ）2. A. read B. great C. meat D. please
（ ）3. A. good B. book C. look D. too
（ ）4. A. laugh B. plough C. cough D. enough
（ ）5. A. season B. master C. husband D. suit
（ ）6. A. resist B. glide C. grinding D. decide
（ ）7. A. bear B. tear C. dear D. fear
（ ）8. A. onto B. month C. long D. wrong
（ ）9. A. it‘s B. its C. his D. this
（ ）10. A. though B. caught C. through D. tough
Exercise 15：
（ ）1. A. hired B. planned C. tried D. defended
（ ）2. A. Germany B. governor C. package D. geography
（ ）3. A. courage B. birdcage C. package D. cottage
（ ）4. A. Saturday B. stay C. daylight D. sway
（ ）5. A. suggestion B. action C. attention D. revolution
（ ）6. A. twenty B. gentle C. entirely D. lend
（ ）7. A. punished B. glared C. saved D. proved
（ ）8. A. shoot B. cool C. cookie D. bamboo
（ ）9. A. healthy B. heavy C. head D. heat
（ ）10. A. north B. worse C. horse D. force