阅读下列各小题，根据括号内的汉语提示，用句末括号内的英语单词完成句子，并将答案写在答题卡上的相应题号后。

66. ---I will study hard and ________________________________(尽力不让父母失望). (let)

   ---You are really a nice boy!

67. ---What was Tom doing when you walked past him?

   ---He ______________________________________(正在找他自行车钥匙).   (key)

68. ---Are you writing to your sister?

   ---Yes. She moved to England last month. She ________________(一定正在盼望收到我的来信). (forward)

69. ---Miss Li, it __________________________________(解出这道题我有困难).   (work)

   ---You may ask Lucy for help.

70. ---Did you meet Mr. Green at the airport?

   ---No. By the time I got there, he _____________________(乘公交已离开十分钟了). (be)

71. ---Jack, it seems that you like to work with animals.

   ---Yes. I think animals ________________________(应该被认为是我们的朋友). (regard)

72. ---Do you like Mrs. Smith?

---Yes. She is_________________________(非常友好,他总是让我有家的感觉). (that)