3 Walking is good. Look at the sun. It's a fine day for walking today.
Because my bike is broken (坏了).
Good morning, Jack! How do you usually go to school?
5 Yes, but not today.
Why?
That's right. And the air is nice and clean today. What about you? Do you often go to school by bike?
I usually go to school by bike. But sometimes I go on foot. I like walking.