71.我一直与大学时代的朋友保持联系。
I keep _______ _______ with my friends from college all the time.
72.铃响了，到上课的时间了。
There ________ the ________. It’s time for class.
73.我的家乡发生了很大的变化。
Great changes have ________ ________ in my hometown.
74.到目前为止，我国政府已经采取了很多措施来控制人口增长。
So far, our government has ________ many ________ to control the population.
75.Tom不在学校，他去医院看医生了。
Tom isn’t at school, he ______ _____ to the hospital to see a doctor.
