6. The lecture has already started.
Present Perfect Tense
The lecture has already started.
How do you know?

8. Present Perfect Tense Examples:
Affirmative: I have seen the film before.
She has seen the film before.
Negative: They haven’t seen the film before.
He hasn’t seen the film before.
Interrogative: Have you seen the film before?
Has she seen the film before?
Who have you seen the film with?
Why haven’t you seen that film?
BUT: When DID you SEE that film?

9. USES OF THE PRESENT PERFECT
1. Recent events:
without a definite time
a time expression may emphasize recentness: just, recently, lately
Why are they so happy?
They have just won a prize so they are really pleased

10. 2. Personal experiences there is not a definite time given
the time expressions ever and never are very often used with this meaning
I have never been to Japan. Have you ever been there?

11. 3. actions that started in the past and continue to the present
the time period is not finished
for and since
FOR with PERIODS OF TIME
SINCE with POINTS OF TIME
I haven’t eaten since yesterday morning. I am really hungry.
I haven’t drunk anything for two days. I am terribly thirsty.

12. signal words: ever just never already (+) since yet (-, ?) for
this morning
so far
this evening
up to now
today
recently
during the last ten days
lately
in the past / last 2 years

13. YOUTUBE SOURCES: OXFORD ONLINE ENGLISH
PRESENT PERFECT TENSE-5 min PRESENT PERFECT vs PAST SIMPLE PRESENT PERFECT EXERCISE PRESENT PERFECT ONLINE PRESENT PERFECT ONLINE EXERCISE PRESENT PERFECT vs PAST SIMPLE EXERCISE ONLINE