We spent a day in the country and picked a lot of flowers. Our car was full of flowers inside! On the way home we had to stop at traffic lights, and there my wife saw the bookshelf.（书柜）
It stood outside a furniture（家具）shop. “Buy it,” she said at once. “We’ll carry it home on the roof-rack（车顶架）. I’ve always wanted one like that.”
What could I do? Ten minutes later I was twenty dollars poorer, and the bookshelf was tied on to the roof rack. It was tall and narrow, quite heavy too.
As it was getting darker, I drove slowly. Other drivers seemed more polite than usual that evening. The police even stopped traffic to let us through. Carrying furniture was a good idea.
After a time my wife said, “There’s a long line of cars behind. Why don’t they overtake（超车）?”
Just at that time a police car did overtake. The two officers inside looked at us seriously when they went past. But then, with a kind smile they asked us to follow their car through the busy traffic. The police car stopped at our village church. One of the officers came to me.
“Right, sir,” he said. “Do you need any more help now?”
I didn’t quite understand. “Thanks, officer,” I said. “You’ve been very kind. I live just down the road.”
He was looking at our things: first at the flowers, then at the bookshelf. “Well, well,” he said and laughed. “It’s a bookshelf you’ve got there! We thought it was——er, something else.”
My wife began to laugh. Suddenly I understood why the police drove here. I smiled at the officer. “Yes, it’s a bookshelf, but thanks again.” I drove home as fast as I could.
From the story we know that                                 .

A．the writer was poor and didn’t buy the bookshelf for his wife

B．the writer’s wife didn’t like the bookshelf at all

C．the writer was not very glad to buy the bookshelf for his wife

D．the writer was always glad to buy something for his wife

What made the writer think that carrying furniture was “a good idea”?

A．Other drivers would let him go first.

B．He could drive slowly and it was safe.

C．His wife could use a new bookshelf.

D．He could save a lot of money and time.

Why were the police and other drivers so kind to the writer?

A．Because they thought the writer liked studying very much and needed a bookshelf.

B．Because they didn’t think it was polite to overtake a car with a bookshelf on it.

C．Because they thought it was dangerous to carry a bookshelf on a car.

D．Because they thought somebody in the writer’s family had died and he needed help.

Why did the writer’s wife begin to laugh?

A．Because the police had helped them a lot.

B．Because at last the police had driven to the church.

C．Because the officer was always looking at the flowers and the bookshelf.

D．Because now she knew what mistake the police had made.

When did the officers begin to realize they had made a mistake?

A．After they arrived at the church.

B．Before they overtook the writer’s car.

C．Before they arrived at the church.

D．After the writer’s family left the church.