1 . 他在火车站偶然遇到了他的一位老校友。
He met with an old schoolmate of his ________ at the railway station.

2 . —Hey, Tom, you are making noise. You should be polite ________.
—Sorry, Mum. I’ve got it.

A．at most

B．in public

C．on time

D．by chance

3 . Success doesn’t come ________, and it depends on days’, even years’ hard work. (偶然)

5 . I met my old friend Lucy by accident yesterday on the street. (改为同义句)
I met my old friend Lucy ________ ________ yesterday on the street.

6 . 昨天下午我偶然遇见了我的英语老师。
I met my English teacher ________ ________ yesterday afternoon.

7 . 萨莉发现她无意中把妈妈的太阳镜装进她的背包里了。
Sally found that she had put her mother’s sunglasses into her backpack ________ ________.

8 . As we all know, success is not made ________. Instead, it needs a lot of talent and hard work. （偶然）

9 . I met an old friend of mine in the street ________ yesterday afternoon. (偶然)

10 . —I’m sorry for taking your book ________.       
—Never mind.

A．by hand

B．by chance

C．by mistake