a number of

1. 一些

A number of people have left.

一些人已走了。

by number

1. 以数字

She knows all the rooms in the building by number and she will tell you where room 324 is.

她知道这幢大楼里所有房间的号码, 她可以告诉你三二四房间在哪里。

in number

1. 在数字上; 总共

We were 30 in number.

我们总共三十人。

number among/in

1. 把……算作

We number him among our friends.

我们把他算作朋友。

number off

1. (列队时)报数

The soldiers numbered off, straight from the right-hand man.

士兵从右边开始报数。

numbers of

1. 许多

Numbers of people came to the meeting.

许多人来参加会议。

one's/the opposite number

1. 对等的人(或物)

An international meeting between each minister and his opposite number will be held next month.

下月将举行部长级的国际会议。

to the number of

1. 达到……的数目; 合计数为

There were people to the number of 100 who had taken part in the competition.

共计有一百人参加比赛。

without number

1. 多得数不清

I have been there for times without number.

我已去过那里无数次。