Present Perfect Tense

1. ���ʴ��˵ء�ó� ���͡�á�зӷ���Դ������¤�������˹�ʹյ ��м��ٴ�����͡���ҷ���˵ء�ó� ���͡�á�зӹ���Դ��� �� adverb of frequency (many times, several times, over and over)

The teacher has taught this lesson many times.
I have watched television several times.
He has read this novel over and over

2. ���ʴ��˵ء�ó����Դ��������ʹյ����˵ء�ó����ѧ���๹�Դ����Ҩ��֧�Ѩ�غѹ �ѡ�� adverb of time (since, for, at last, recently, lately, so far, up to now, up to the present time)

My son has studied in Australia since 2000.
Jim hasn't written to me for nearly a month.
He has worked in this company for 5 years.
I haven't smoked for three years.
He has ever been a doctor up to now.

3. ���ʴ��˵ء�ó�����觨�ŧ���� � �ѡ�� adverb of time (just, already, yet)

She has just had lunch.
The train has just arrived.
They have seen this movie already.
The train has arrived already.
He hasn't done his homework yet.
He hasn't finished the work yet.
Has it stop raining yet?
I haven't told them about the accident yet.

4. ��Ѻ����ʴ��֧����� ��������� �ѡ�դ� never, ever, once, twice... ����������

Have you ever been to Hong Kong?
Yes, I have been there twice.
No never. I have nevr been abroad.
Have you ever eaten Somtam?
We have never had a car.
He has ever been to Japan.

5. �֡�Ҥ���ᵡ��ҧ�����ҧ gone to ��� been to

Keth is on vocation. She has gone to Italy.
(���͹��������㹢�й�� �������͹����������ҧ����Թ�ҧ价����)
Tom is back from his vacation. He has been to Italy.
(������������� ��͹����ҡ�Ѻ������)

6. �������ʴ����������� � �������ͻ�С������˵ء�ù����觨��Դ���

I has lost my key. Can you help me look for it?
Did you hear about Jim? He 's gone to Japan.