一、 现在完成时分“已完成”和“未完成”两种用法：
1.“已完成”指的是动作发生在过去,强调其对现在产生的影响.如：
John has broken his left leg. 约翰摔断了左腿.(意思说他现在不能走路了,或者……)
I have seen this film. 我看过这部电影.(意思说我已经知道了电影的内容.)
“已完成”这种用法一般不带时间状语,但可以和already, yet, before, ever, just, now等副词连用.如：
Have you ever been to Qinghai ? 你去过青海吗?
He has never said he is rich. 他从来不说他有钱.
2. “未完成”指的是动作从过去开始,且一直继续到现在.因此不能用表示瞬间性的或称短暂性的动词.“未完成”的现在完成时常与since结构或“for+一段时间”的状语连用.如：
I have lived here since I was born. 我一出身就住在这里.
He has been a League member for three years. 他入团已有三年了.
“未完成”这种用法还常与until now, so far, in/during the past/ last...等连用.如：
I’ve been here for three weeks, and so far I’ve enjoyed it. 我已在这儿逗留了三个星期,到现在为止,我过得挺快活.
In the past ten years many new schools have been built up in our city. 过去十年中我市已兴建了许多新学校.
二、现在完成进行时与现在完成时的“未完成”用法类似.它强调动作的延续,常常译做“一直在……”.其基本用法有三个：
1.现在完成进行时表示从过去开始、现在仍在继续的动作.其时间状语除了since结构和for结构外,还有all this time, this week, this month, all night, all the morning, recently等状语. 如：
I’ve been waiting for an hour and he still hasn’t turned up. 我等了一个小时,可他还没来.
He has been watching TV all the morning and has done nothing. 整个上午他一直在看电视,什么事情都不做.
2. 现在完成进行时还用来表示从过去开始、现在刚刚结束的动作.如：
I’m sorry I’m late. Have you been waiting long? 真对不起,我迟到了.你等了很久了吧?
I’ve been writing letters all this evening and I’ve just finished them. 整个晚上我一直在写信,现在刚刚结束.
3. 现在完成进行时还可以用来表示反复的、连续的动作.如：
I’ve been knocked at the door. I don’t think anybody is in. 我一直在敲门.我想屋里没有人.
She has been telephoned her husband, but there is no answer. 她一直在给她丈夫打电话,但没有人接.