When we talk about a period of time that continues from the past until now, we use the present perfect tense...We use present perfect tense with today, this morning, this year etc. when these periods are not finished at the time of speaking...We say 'It's the (first) time something has happened'.
We use the present perfect continuous tense (I have been doing) for an activity that has recently stopped or just stopped...(Another example: It's been raining for two hours. It began raining two hours ago and it is still raining.) We use the present perfect continuous tense like this example, especially with 'how long, for...and since...'. The activity is still happening (as in this example) or has just stopped. You can use present perfect continuous tense for repeated actions (since, for).
Source: Cambridge
沒有留言:
發佈留言