Since vs. For with Present Perfect

Since is used with the present perfect to express that something has happened since a point in time.
I've lived here since 1999.
She's been working hard since two this afternoon.

For is used with the present perfect to express that something has happened for a period of time.
I've worked at this job for 10 years.
Peter's been playing tennis for two hours.

"at your English Tips 6"

Preposition + Verb
Always use the gerund when the verb is the object of a preposition
What shall we do? - How about visiting Tom!
I looked into purchasing a new computer.

Interested In
The correct usage of showing interest is a passive infinitive "to be interested in".
They are interested in geography.
Was he interested in coming to the presentation?

Good and Bad
The comparative form for "good" is "better". The superlative form is "the best". The comparative form for "bad" is "worse". THe superlative form is "the worst".
She is the worst tennis player on the team.
He's better at math than Jack, but worse at geography.

The Basics of "At"
Use "at" with times of the day and places in a city.
I'll meet you at three o'clock.
Let's meet at the bank.

Ask
The verb "ask" plus an object is constructed "S + ask + person being asked + infinitive with to".
She asked him to repeat the question.
My friend asked me to come early to the meeting.


On
Use "on" with days of the week. However, in British English use "at the weekend".
I'll see you on Tuesday.
Let's meet on Sunday.



Since
Use the present perfect (continuous) with the time expression "since" when using a specific date or time.
He's lived in that house since 1998.
They've been playing golf since ten this morning.