A:The weather is changeable. What kind of weather do you like best?
B:I like rainy days.
A:Why?
B:Because they make the world wet.In a highly-industral world today,the air is not as pure as it used to be. Rainy days make the world cleaner,doesn't it?
A:That may be right. But rainy days also bring us some trouble. It's very unconvenient to go outside on rainy days.
B:It seems to be true.Look, it's raining outside. Let's go out and feel it!
B:That's a good idea.