A、Because he was carrying a heavy load. B、Because it was getting dark. C、Because it was raining. D、Both A and B. D

We spent a day in the country, picking wild flowers. Our car looked like a florist’s shop at the traffic lights; and there my wife noticed the cupboard.
    It was tall and narrow, and it stood on the pavement outside a furniture shop. "Buy it," she said at once. "We’ll carry it home on the roof rack. I’ve always wanted one like that."
    What could I do? Ten minutes later I was ＄20 poorer, and the cupboard was tied onto the roof rack. It was 6 feet long and 18 inches square, quite heavy too.
    In the gathering darkness I drove slowly. Other drivers seemed unusually polite 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, I wonder?"
    In fact a police car did overtake. The two officers inside looked at us seriously as they passed. But then, with great kindness, they led us through the rush-hour traffic. The police car stopped at our village church. One of the officers came to me.
    "Right, sir," he said, "do you need any help now?"
    I was a bit puzzled. "Thanks, officer," I said, "You’ve been very kind. I just live down the road."
    He was staring at our load: first at the flowers, then at the cupboard. "Well, well," he said, laughing. "It’s a cupboard you’ve got there! We thought it was something else."
    My wife began to laugh. Then the truth hit me like a stone between the eyes. I smiled at the officer. "Yes, it’s a cupboard, but thanks again." ! drove home as fast as I could.