⒋ 现在完成时和一般过去时的区别
现在完成时和一般过去时都表示在过去完成的动作。但现在完成时强调的是这一动作与现在的关系。如对现在产生的结果或影响等，而一般过去时只表示动作在过去某一时刻发生，不表示和现在的关系。试比较：
I have lost my new book. 我把新书丢了。(现在还未找到)
I lost my new book yesterday. 我昨天把新书丢了。(昨天丢的，现在找到与否没说明)
The light has gone out.灯已经息了。(现在尚未亮)
The light gone went out.灯曾经息过。(现在已亮了)
⒌ 几点注意事项
I. have been(to)与have gone( to)的区别：
have been(to)表示“去过某地(现在已经回来了)”，可用于各人称；have gone(to)表示“去某地了(说话时某人不在当地)”，常用于第三人称，前者可与once ，never，several times等连用，后者则不能。如：
They have been to Beijing twice.他们去过北京两次。
He has gone to Beijing . 他去北京了。
II. 如单纯表示一段时间，或强调一段时间，虽有since一词，也不必用完成时。如：
It is two years since his father died. =His father has been dead for two years.他父亲去世已有三年了。
Ⅲ. 不可延续性动词现在完成时的否定式，已变成一种可以延续的状态，因此可以和表示一段时间的状语连用。如：
I haven’t left here since 1997.自从1997年以来，我一直没有离开过这儿。
(错)I have received his letter for a month.
(对)I haven’t received his letter for almost a month.
⒍ 用于现在完成时的句型
Ⅰ.It is the first / second time…. that…结构中的从句部分，用现在完成时。
It is the first time that I have visited the city.
Ⅱ.This is the… that…结构，that 从句要用现在完成时。
This is the best film that I’ve (ever) seen. 这是我看过的最好的电影。
动词时态经典例题解析：
1. --- Oh， dear. I forgot the air tickets.
--- You ______ something.
A. have left B. are always leaving C. are leaving D. always left
解析：进行时态与always， all the time等连用，表示习惯性行为，且带有浓厚的感情色彩。此处可理解为“你总是丢三落四的”。，所以这个应该选B
2. --- I ______ so busily recently that I ______ no time to help you with your maths.
--- That’s OK. I can manage it by myself.
A. have been working; have B. have worked; had
C. am working; will have D. had been working; had had
解析：recently常与现在完成时或一般过去时连用。第二空应用一般现在时。所以这个应该选A
3. Remember to send me a photo of us next time you ______ to me.
A. are writing B. will write C. has written D. write
解析：next time引导时间状语从句，而且其谓语动词常用一般现在时表示将来。所以这个应该选D
4. He ______ at the meeting， but his heart attack prevented him.
A. will speak B. is going to speak C. had to speak D. was going to speak
解析：由题意“他本来打算在会上发言，但……”可知应选D项。
5. --- I beg your pardon， but I didn’t quite catch you.
--- Oh， I ______ myself.
A. am talking to B. talked about C. have talked to D. was talking to
解析：Oh， I was talking to myself.意为“噢， 我(刚才)只是在自言自语”。 所以这个应该选D.
6. I ______ ping-pong quite well， but I haven’t had time to play since the New Year.
A. will play B. have played C. played D. play
解析：“乒乓球打得好”是一般情况，故用一般现在时。所以这个应该选D.