1. 〔誤〕 He became a writter at his twenties 〔正〕 He became a writter in his twenties
〔析〕這句話應譯爲：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。
2. 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 Years Day
3. 〔誤〕 Im looking forward to seeing you on Christmas. 〔正〕 Im 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是聖誕節期間，一般要有兩週或更長的時間。
4. 誤 I havent see you during the summer holidays. 正 I havent 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，可以用於完成時，如：I havent see you for a long time. 而through 用來表示時間時則爲"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。
5. 〔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)
6. 〔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，均不指時間範圍，而in the beginning 則是指開始一段時間。in the end=at last是指"最終，終於"之意。
7. 〔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，其意思爲"不遲於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：Ill be there by five oclock.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 wont finish this work till(until) next weekend.
8. 〔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。
9. 〔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爲過去時，而不能用完成時態
10. 〔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後來取，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 多用於過去時，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範圍，如：after three days, 即三天之後的哪一天都可以。所以在許諾若干時間內會完成某事時，一定要用介詞in。
