1. a．She wrote a letter to her friend last night. b．She was writing a letter to her friend last night. 2．a.It rained the whole evening. b．It was raining the whole evening. 3. a．I was leaving the office when the telephone rang. b．The light went out while we were having supper. 4. a．I saw my English teacher on the street yesterday. b．She was looking for a job at this time last year. 5．a.Last year I always went to the theatre. b．He was always throwing things about.

Ⅰ.一般过去时和过去进行时