1. (2021八上·南山开学考)  阅读下面短文，从短文眉所给的A、B、C、D四个选项中选出能填入相应空白处的最佳选项。

There was a little boy called Lewis. One day, Lewis's father 1  him to school, and Lewis saw a large mass（一团）of gray smoke coming from the car. So Lewis asked his father,"Dad, what's that gray smoke coming from our car?"

Lewis's father answered,"It's a kind of air 2 . Cars need petrol to run. Then smoke comes from cars and goes into the air. It's 3 for our health and the earth.

Lewis started to think, He felt sad about the pollution 4 . "Dad, if the gray smoke is bad for us,why are we going to school by car now?"said Lewis 5 .

"Because we can get to school and work on time, son. The bus or subway would make us 6 . " answered his father.

From that morning, Lewis couldn't stop 7 why people used cars so much. He wanted to do something. The next day,when Lewis's father came to 8 him up, he told his father, "Dad, we could come to school by 9 from tomorrow. If there isn't enough time, we just need to get up early. We should do something 10 for the environment. " From that day on, Lewis and his father always went to school and work by bus.