in，on，at的时间用法和地点用法在英语中介词的使用频率比较高，而介词in, on和at 又是介词中使用频率比较高的词。一、介词in, on和at时间用法1、in的时间用法1）、在某个较长的时间（如世纪，朝代，年，月，季节，及泛指的上午，下午和晚上等，假期）内。在泛指的上午、下午、晚上前。如：in the morning，in the afternoon，in the evening，in the early morning在大清早在年、月、季节前。如：in ，in August，in summer，in spring在春天，In June在六月，in June,在六月,He was born in 1942.在假期、在某段时期内in the holidays，in ones youth，in ones spare time在某人业余时间 , in my free time在我空闲时，in ones childhood在童年, in recent years，in course of , in the future 在将来, in future 从此后来=from now on，in the past，in my teens在我十几岁时，in his eighties在她八十多岁时，in a day or two在一两天，in those days在当时，in the old days在过去的日子里，in a month/year在一种月/一年里（在将来时里翻译成一种月或一年后）在世纪、朝代、年代前In the 20th century，in the 21st century (除了1st,2nd,3rd 以外，其她序数词以th结尾)， in the eighties 在八十年代，in the 1990s或in the 1990s在九十年代2）、在一段时间in a month/year在一种月/年里（在将来时里翻译成一种月/年之后）in the day（time）在白天，可换成duringin my childhood在我的童年里in my free/leisure time在我空闲时，in可换成during，也可以写成at leisure在空闲时。He will come round in a day or two.I will finish it in three hours.3）在某些较短时间在开始，在结束，在某一时刻In the beginning, in the end, in the meantime同步，in broad day在大白天，in seconds在很短时间内，in time 准时，in a second立即4)、固定短语：in time及时 （on time 准时，及时指在事情未晚之前做成，强调最后期限。准时指在指定期间时间做成。）in the day（time）在白天，可换成during；2、on的时间用法On指时间表达：1）、以day结尾的节日前on New Years Day, on Childrens Day，On Christmas Day，on Teachers Day在教师节（注意：节日里有表人的词汇先复数再加s所有格，如on Childrens Day, on Womens Day, on Teachers Day有四个节日强调单数之意思，on Mothers Day, on Fathers Day, on April Fools Day, on Valentines Day）2)表达具体日期“在某月某日”： on + 月份+ 序数词(th可省略, 但读时要念出来)，如：National Day is on Oct. 1. On May 4th，on June 2nd在六月二日 on + the + 序数词+ of + 月份。如：on the 5th of MayNational Day is on the 1st of October. on the second (of June 2nd)在六月的第二天即在六月二日其她日期表达措施on the last Friday of each month 在每月的最后一种星期五on the second day在第二天（以过去某天为参照）注意：on Sunday在周日，on Sundays每逢周日（用复数表每逢之意），every Sunday每个周日，基本一种意思。on a school day 在某个上学日，on school days每逢上学日。on the weekend在周末，on weekends每逢周末3）在星期几On Sunday4）在生日前on my ninth birthday在我九岁生日那天on ones birthday5）在某个特定的上午，下午或晚上He arrived at 10 oclock on the night of the 5th.He died on the eve of victory.on Sunday morning在周日上午on the morning of June 2nd在六月二日的上午on a rainy morning在一种多雨的上午on a winter morning在一种冬天的上午on Sunday night在周日晚上on a rainy night再一种多雨的晚上on the night of June 2nd在六月二日的晚上on school days/nights在上学日/上学的当天晚上用法对比我们再来横向比较一下，以morning 为例：in the morning在上午early in the morning再大清早on Sunday morning在周日上午6）习常用法on a certain day 在某天on time准时，准时on the weekend在周末（英式用at the weekend在周末， at weekends每逢周末）on weekday在工作日on the moment(立即),3、at的时间用法表达时间的一点，一时刻。如：at seven oclock，at 6:00在六点，at noon, at midnight, at ten oclock, at daybreak, at dawn，at this time/moment (of day)在（一天中的）这个时间，at that time/moment (of year)在（一年中的）那个时间，at the start of the concert在音乐会开始在老式节日前。如：at Spring Festival，at Mid-Autumn Festival，at Christmas (time) 在圣诞节时（注意，如果用on，写成on Christmas Day），at New Yearat breakfast/lunch/dinner在早餐/午餐/晚餐时at meals在三餐时较短的一段时间。可指某个节日或觉得一年中标志大事的日子His grandfather died at seventy-two.At the beginning (middle, end) of that month he was sick.at the age of ten在十岁时，at forty在四十岁时at the end/beginning of last term在上学期结束/开始，过去时的时间。（by the end of last term直到上学期期末，过去完毕时的时间。注意 in the end最后/终于=finally=at last）固定搭配。如：at once（立即，立即）be good at（擅长）look at（看）at home（在家），at school（在学校）, at the back of（在后部）at weekends（在周末）at any time 随时at the correct/proper time 在对的的时间at the same time 同步 或者in the meantime 同步，于此同步at times 偶尔，时常at festivals每逢节日 （用复数表每逢。如强调时间范畴则用during festivals） at first/last首选/最后at down在黎明时，at daybreak 在天亮时，at sunrise 当天出时， at dusk在傍晚时at sunset 在日落时，at dark在天黑时at night在夜晚 （注意during the night=in the night翻译成在夜晚期间，强调这个时间范畴）late at night在深夜at midnight 在半夜，at present在目前at the stage(眼下)at noon/night在中午/夜晚, （不强调范畴，强调的话用during the night）early in the morning=in the early morning在大清早，late at night在深夜at all times(始终)at times(有时）at a time(在某时)at that timeat dinner-timeat the same timeat the time ofat this time of dayat the time beingat nightfallat that moment, at the age of, at the beginning of , at the end of, at the last minute, at the moment, at the present stage , at the start, at the very start, at this point(此时), at this season, at a wedding(婚礼), at any moment, at Easter, at first sight,(一见到), at sunrise4、不加介词this, that, last, next, every, one, yesterday, today, tomorrow, tonight，all，most等之前一般不加介词。如，this morning今天上午（on）that day在那天 （that day更常用些）last week上周next year来年the next month第二个月（以过去为起点的第二个月，next month以目前为起点的下个月）every day每天one morning一天上午yesterday afternoon昨天下午tomorrow morning明天上午all day/morning/night成天/整个上午/整晚（等于the whole day/morning/night）most of the time （在）大多数时间this morning今天上午yesterday morning昨天上午tomorrow morning明天上午the next morning第二天上午every morning每天上午one mo