18. The boy was able __ the piano when he was small. D. to going A. play B. to playing C. to play D. played 19. Would you like __ with music? A. danced B. to dance C. dancing D. to dancing 20. Have you ever expected __ an astronaut? A. to become B. to becoming C. becoming D. to receiving 21. Try __ so many mistakes for the next easay about describing one of the most favorite heritage sites in the world. A. not to make B. not make C. to make not D. make not 22. I must go now . I promised __ late for the trip to Sa Pa. A. not being B. not to be C. not being D. won't be 23. It was 11 pm. so we needed __ a taxi home. A. to take B. taken C. taking D. take 24. Lily always encourages her son __ harder to get a better place at the University. A. to study B. studied C. study D. studying

18. **C. to play**<br /><br />The correct structure is "be able to + base verb". "Able" is followed by the infinitive form of the verb.<br /><br />19. **B. to dance**<br /><br />The phrase "Would you like" is followed by the infinitive form of the verb.<br /><br />20. **A. to become**<br /><br />The verb "expect" is followed by the infinitive form of the verb.<br /><br />21. **A. not to make**<br /><br />The verb "try" can be followed by either an infinitive or a gerund, but in this case, "not to make" is the correct and more natural choice to express the intention of avoiding mistakes.<br /><br />22. **B. not to be**<br /><br />The verb "promised" is followed by the infinitive form of the verb. "Not to be" correctly expresses the promise to avoid being late.<br /><br />23. **A. to take**<br /><br />The phrase "needed" requires the infinitive form of the verb to complete the sentence correctly.<br /><br />24. **A. to study**<br /><br />The verb "encourages" is followed by the infinitive form of the verb.<br />