part2: rewrite the sentences without changing the meaning with the cue words(1pt) 37. David had gone home before we arrived. =>After____________________________________________________________ 38. They can't make tea with cold water. =>Tea_______________________________________________________________ 39. How long have you learnt English? =>When______________________________________________________________ 40. People throw rubbish in the streets. The streets are dirty. =>If______________________________________________________________ 41. David had gone home before we arrived. =>After______________________________________________________________ 42. We had lunch then we took a look around the shops. =>Before______________________________________________________________ 43. The light had gone out before we got out of the office. =>When______________________________________________________________ 44. After she had watered all the plants in the garden by the time my mother came home. =>Before______________________________________________________________ 45. My father had watered all the plants in the garden by the time my mother came home. =>Before______________________________________________________________ giúp mình với