pron det (1)一(个)，单个(single;individual)：～dog and three cats 一条狗和三只猫;O～swallow does not make a summer. (prov) 孤燕不成夏。Put～piece of cake on each plate.每个盘子里放一块点心。There's only～thing to be done，as far as I can see.在我看来，只有一件事要做。

(2)某一(时间)(noting some indefinite time)：～morning/day/week last month 上个月的一个早晨/一天/一周;I'll have to retire～day，but that's a long way off.总有一天我得退休，不过现在离那时还远着呢。O～time I kind of figured on becoming an X-ray specialist.一度我还有点儿想当X光专家呢。

(3)某(人或物)(particular(person or thing))(重读，用以加强语气)：He is the～man who can do it.他就是那个能做这件事的人。That's the～thing I need.那正是我需要的一件东西。

(4)某个(位)(certain...) (fml)(用于姓名前表示说话者不知其人)：O～John Brown telephoned.有个叫约翰·布朗的人来过电话。I heard the news from～Mr. Smith.我从一位史密斯先生那里听到这个消息。

(5)这一个的(表示与别的对照)(used to designate a person or thing that is contrasted with another，the other or others)： He was at～end of the hall and I was at the other.他在大厅的这一端，而我在另一端。Well，that's～way of doing it，but there are other and better ways.不错，那是做这件事的一种方法，不过还有别的更好的方法。The little boy can't tell～dog from another.那个小男孩区别不出这只狗和那只狗。

(6)同一(the same;of the same opinion，etc)：We are of～mind on this matter.在这件事情上我们想法一致。With～accord the audience rose and sang the national anthem.听众全体起立高唱国歌。

(7)一个确实(非常)……的(used instead of a or an to emphasize the noun or phrase that follows it)(替代a或an，强调其后的短句)(infml)(无AmE)：She's～beautiful girl.她确实是个漂亮姑娘。He's～troubled man.他麻烦重重。

be at one(with sb/sth)与……相同(一致)：Husband and wife were at～on everything but money.丈夫和妻子除了钱之外在其他方面意见都一致。

for one 例如……(就是一个)：I for～，can not agree.起码我就不能同意。

(all) in one 合在一起：Jerry is like a father and a mother in～.杰里又当爹又当妈。

one after another/the other 一个接一个，相继，陆续：O～after another they refused to sign.他们相继拒绝签名。

one and all 人人，大家(infml)：Thank you～and all for the present.感谢你们大家的礼物。

one and only 唯一的，仅有的(用以加强语气)：This is my～and only coat.这是我仅有的一件大衣。

one and the same 同一的，完全一样的：Your boyfriend and my brother are～and the same.你的男友和我的兄弟是一个人。

one by one 一个一个地，逐一：The boss wants to see the staff members～by～.老板打算逐一见见每一个成员。

one or two 几个，一两个：There are～or two minutes left for questions.还留有几分钟提问题。

one up (on/over sb)略胜某人一筹，领先某人一步：John graduated from high school;he is～up on Bob，who dropped out.约翰高中毕业，比鲍勃强。鲍勃中途就退学了。