题目

阅读短文，根据短文内容，从短文后的五个选项中选出能填入空白处的最佳选项。选项中有一项为多余选项。 One day, the father of a very rich family took his son on a trip to the countryside. He wanted to show his son how poor people lived. ____1_____.On their returen from their trip, the father asked his son, “How was the trip?”  “_______2_____.”  “Did you see how poor people live?” the father asked.  “Oh yeah,” said the son.  “So, tell me, what did you learn from the trip?” asked the father.  The son answered,“We have on为了减少空气污染，北京市积极推广使用清洁燃料。目前汽车使用的清洁燃料有两类，一类是液化石油气（LPG），另一类是压缩天然气（CNG）。压缩天然气的主要成分为（    ） A.C2H5OH            B.CH4             C.CO             D.H2