Question

but, take place, in the past, go to work, used to be

Over the past ten years, great changes (1)_________ in our hometown. (2) ______, the houses in our hometown were very old, (3)_________ now most of the people have moved into tall buildings. The water in the river (4)_________ very dirty, but now the river is very clean, and we can swim in it. People here used to walk or ride bikes, but now they can take buses or drive their own cars (5)_________.

Answer

  have taken place        

  In the past              

 but      

 used to be                

 to go to work

【解析】

 此题考查动词短语，根据语境可知近十几年我家乡发生了很大的变化，故用动词短语take place，要用现在完成时的形式。

 此题考查介词短语，根据下文的now可知要用in the past表示在过去。

 此题考查介词，根据上下文可知表示转折，现在和过去相对比，故用but。

 此题考查动词短语，根据语境可知描述的是以前的小河的情况。故用used to be。

 此题考查动词不定式做目的状语，现在的人们开车去上班。