[誤] We got to the top of the mountain in daybreak.

[正] We got to the top of the mountain at day break.

[析] at用于具體時刻之前，如：sunrise， midday， noon， sunset， midnight， night.

[誤] Don’t sleep at daytime

[正] Don’t sleep in daytime.

[析] in 要用于較長的一段時間之內，如：in the morning / afternoon， 或 in the week / month / year. 或 in spring / supper /autumn / winter等等。

[誤] We visited the old man in Sunday afternoon.

[正] We visited the old man on Sunday afternoon.

[析] in the morning， in the afternoon 如果在這兩個短語中加入任何修飾詞其前面的介詞都要改為on， 如：on a cold morning， on the morning of July 14th

[誤] He became a writter at his twenties

[正] He became a writter in his twenties

[析]這句話應譯為：他在20多歲時就成了作家。在某人的一段生活時間段中要用介詞in來表示，而在具體歲數時用at來表示。

[誤] He went to New York to find a job in sixteen years old.

[正] He went to New York to find a job at sixteen.

[析] 在具體年歲前用at， 如：at the age of 12， at your age，等等。

[誤] We went to swim in the river in a very hot day.

[正] We went to swim in the river on a very hot day.

[析] 具體某一天要用介詞on， 又如：on New Year‘s Day

[誤] I’m looking forward to seeing you on Christmas.

[正] I’m looking for ward to seeing you at Christmas.

[析]在節日的當天用on，而全部節日期間用at，Christmas是圣誕節期間，一般要有兩周或更長的時間。

[誤] I haven’t see you during the summer holidays.

[正] I haven’t seen you since the beginning of the summer holidays.

[析] during表示在某一段時間之內，所以一般不與完成時搭配，如：I visited a lot of museums during the holiday. 而for表示一段時間，可以用于完成時，如：I haven‘t see you for a long time. 而through 用來表示時間時則為“整整，全部的時間”。如：It rained through the night.而since則是表達主句動作的起始時間，一般要與完成時連用。

[誤] At entering the classroom， I heard the good news.

[正] On entering the classroom， I heard the good news.

[析] On 加動名詞表示“一……就”。本句的譯文應是：我一進入教室就聽見這個好消息了。又如：on hearing… 一聽見， on arrival 一到達就……(on表示動作的名詞)

[誤] In the beginning of the book， there are some interesting stories.

[正] At the beginning of the book， there are some interesting stories.

[析] at the begining與at the end都是指某事物的開始與結束部分，均不指時間范圍，而in the beginning 則是指開始一段時間。in the end=at last是指“最終，終于”之意。

[誤] Till the end of next week. I will have finished this work.

[正] By the end of next week. I will have finished this work.

[析] by 引起的時間狀語表示了動作的截止點，其意思為“不遲于某一時刻將工作做完”，所以主句一般是完成時態。當然可以有將來時態，如：I‘ll be there by five o’clock.而till則表達其一動作一直持續到某一時刻，但句中的動詞一定要用持續性動詞，而瞬間的截止性動詞應用其否定句式，如：I won‘t finish this work till(until) next weekend.

[誤] He came to London before last weekend.

[正] He had come to London before last weekend.

[正] He came to London two weeks ago.

[析] before 一般要與完成時連用，而ago則與一般過去時連用。

[誤] I have studied English for three years gince I had come here.

[正] I have studied English for three years since I came here.

[析] since用來表達主句動作的開始時間，所以其引出的從句中應為過去時，而不能用完成時態

[誤] I can help you repair this bike. You will get it after two hours.

[正] I can help you repair this bike. You will get it in two hours.

[析]中文經常講兩小時之后來取，兩天內會修好，而這個介詞在英文中要用in而不要用after.其原因有二，①after 多用于過去時，如：I arrived in New York. After three days， I found a job in the bank. ② after 加時間是表達一個不確定的時間范圍，如：after three days， 即三天之后的哪一天都可以。所以在許諾若干時間內會完成某事時，一定要用介詞in.