- one of the twenty-four-hour periods, reckoned from one midnight to the next, into which a week, month, or year is divided, and corresponding to a rotation of the earth on its axis一天。
- the part of this period when it is light白昼;
- the time between sunrise and sunset白天, 日间：
the animals hunt by day.
这些动物日间猎食。
- the time spent working during such a period工作日：
he works an eight-hour day.
他一天工作八小时。
- Astronomy a single rotation of a planet in relation to its primary【天文】自转周期; 日, 恒星日。
- Astronomy the period on a planet when its primary star is above the horizon【天文】（天体）白昼。
- mass noun archaic daylight〈古〉日光：
by the time they had all gone it was broad day.
到他们都走了的时候天已大亮。
- （一般作days）a particular period of the past; an era（过去的）时期; 时代：
the laws were very strict in those days.
在那个时代法律是很严厉的。
the day
the present time现在, 目前：the political issues of the day.
目前的政治问题。
- usu. with modifier
days
a particular period in a person's life or career（人生）时期, 时代, 生涯： my student days.
我的学生时代。
one's day
the successful, fortunate, or influential period of a person's life or career（人生或事业的）风光时期, 鼎盛时期, 如意时期：he had been a matinée idol in his day.
他曾是风光一时的日场演出偶像。
one's days
the remaining period of someone's life余生：she cared for him for the rest of his days.
她照料他的余生。
- carried out during the day as opposed to the evening or at night白昼的, 日间的：
my day job.
我日间的工作。
- (of a person) working during the day as opposed to at night（人）日间工作的, 白天工作的, 上白班的：
a day nurse.
日间护士。
all in a （或the） day's work
- (of something unusual or difficult) accepted as part of someone's normal routine or as a matter of course（特别或困难的事）日常的, 家常便饭的：
dodging sharks is all in a day's work for some scientists.
对一些科学家来说躲避鲨鱼是家常便饭。
any day
- informal at any time〈非正式〉任何时候, 随便哪一天：
they could outfight the police any day.
他们随时都可以打败警方。
- (used to express one's strong preference for something) under any circumstances［用于表达某人对某事物强烈的偏好］无论何时, 在任何情况下：
I'd rather have Ruth than you, any day.
什么时候我都宁愿要露丝不要你。
- very soon很快：
she's expected to give birth any day now.
她很快就要生产了。
at the end of the day
- 见END.
by the day
- gradually and steadily逐渐平稳地：
the campaign is growing by the day.
运动日益蓬勃。
call it a day
- decide or agree to stop doing something到此为止。
day after day
- on each successive day, especially over a long period日复一日：
the rain poured down day after day.
一天又一天大雨倾盆。
day and night
- all the time日日夜夜, 夜以继日：
the district is patrolled day and night.
该地区有人日夜巡逻。
day by day
- on each successive day; gradually and steadily一天天地：
day by day I grew worse.
我的情况一天天地越来越糟。
day in, day out
- continuously or repeatedly over a long period of time日复一日, 一天又一天。
day of reckoning
- the time when past mistakes or misdeeds must be punished or paid for; a testing time when the degree of one's success or failure will be revealed清算的日子, 报应到来的时刻, 最后审判日。
- ORIGIN: with allusion to Judgement Day, on which (in some beliefs) the judgement of mankind is expected to take place
don't give up the day job
- informal used as a humorous way of recommending someone not to pursue something at which they are unlikely to be successful〈非正式, 幽默〉做好眼下的工作（劝告某人不要追求不可能成功的事情）。
from day one
- from the very beginning从一开始：
children need a firm hand from day one.
孩子们从一开始就该严格管教。
have had one's （或its） day
- be no longer popular, successful, or influential不再风光, 不再流行：
power dressing has had its day.
显贵穿着已经过时了。
if he （或she 等） is a day
- at least (appended to a statement about a person's age)至少（加在关于某人年龄的话语之后）：
he must be seventy if he's a day.
他肯定至少有70岁了。
in this day and age
- at the present time现在。
not someone's day
- used to convey that someone has experienced a day of successive misfortunes背运日。
- of the day
- a thing currently considered to be particularly interesting or important当日热点（或焦点）：
the big news story of the day.
当日的热点新闻。
one day（或some day, one of these days）
- at some time in the future有一天：
our wishes will come true one of these days.
我们的愿望总有一天会实现。
one of those days
- a day when several things go wrong倒霉日。
that will be the day
- informal that is very unlikely〈非正式〉不可能。
these days
- at present现在, 目前：
he's drinking far too much these days.
他最近喝得太多了。
those were the days
- used to assert that a particular past time was better in comparison with the present［用于表示与现在相比, 过去的某个时期更好］那个好时候。
to the day
- exactly整整：
it's four years to the day since he was killed.
自他被杀已有整整四年了。
to this day
- at the present time as in the past; still至今依然, 仍然：
the tradition continues to this day.
此传统流传至今。