51. My brother ________(make) o many American friends since he went there two years ago.

50. Our physics teacher ____________________(not come)to work today，because he is ill.

49. ________ the train _________(arrive)?---No，not yet.

48. My grandson ______________(be)ill for a week.

47. We _______ already _______(draw)five pictures.

46. How long _______ your mother _______(teach)English in this school? ---For ten years.

45. ______she ______(tell)you the good news? ---No，she _______.

44. ______ you______(visit)the Science Museum? ---Yes，I________.

43. Where _____he ______(be)? He _________(be)to the bank.

42. They ______ just _______(talk)about you.