题目

A rich father took his son on a trip to a village. He wanted to show his son what are the differences ______ their life and the villagers’, so that his son could cherish(珍爱)what he had. They spent______ a few days with a family there.On their way back home, the father ______ about his son’s ideas about the trip. So he asked,“ ______ was the trip?”“It was great, Dad!”“What did you learn from the trip?”the father couldn’t ______ to ask. The son answered, “We have one dog but the family has four. We have a swimming pool. but they have a big river with many ______ swimming 炎热的夏天，路面会拱起开裂，小明通过查阅资料得知：这是由于受热膨胀引起的。物质具有热胀冷缩现象的主要原因是（ ）A.微粒的性质发生了改变B.微粒的大小发生了改变C.微粒的质量发生了改变D.微粒间的间隔发生了改变