51. My little brother sleeps nine hours every day. (划线提问)

　 　How ________ hours _________ your little brother sleep every?

50. We should eat a _________ (balance) diet　 to stay healthy.

49. There are sixty _________ (minute) in an hour.

48. We’re __________ (leave) for Beijing for vacation next week.

47. I’m planning __________ (spend) time in the beautiful countryside.

46. Thank you for __________ (invite) me.

45. I can’t go to the movies this Saturday. I have to have my piano l__________.

B) 用所给词的适当形式完成下列句子。

44. Mary is t_________. Please bring her some water.

43. You should drink some hot tea w_________ honey.

42. Maria e__________ every day, so she is in good health.