We use still to show that something continues up to a time in the past, present or future. It goes in front of the main verb:
Even when my father was 65, he still enjoyed playing tennis.
It's past midnight but she's still doing her homework.
I won't be at work next week. We'll still be on holiday.
or after the present simple or past simple of be:
Her grandfather has been very ill, but he is still alive.
We tried to help them, but they were still unhappy.
No longer
We use no longer to show the idea of something stopping in the past, present or future. It goes in front of the main verb:
At that moment, I realised that I no longer loved him.
We no longer live in England. We've moved to France.
From midnight tonight, Mr Jones will no longer be the president.
or after the present simple or past simple of be:
Sadly, Andrew and Bradley are no longer friends. They had an argument.
It was no longer safe to stay in the country. We had to leave immediately.
In a negative sentence, we use any longer or any more. It goes at the end of the sentence:
We don't live in England any longer.
It wasn't safe to stay in the country any more.
Already
We use already to show that something has happened sooner than it was expected to happen. It goes in front of the main verb:
The car is OK. I've already fixed it.
It was early but they were already sleeping.
or after the present simple or past simple of be:
It was early but we were already tired.
We are already late.
Sometimes already comes at the end of the sentence for emphasis:
It's very early but they are sleeping already.
It was early but we were tired already.
When we got there, most people had arrived already.
Yet
We use yet in a negative or interrogative clause, usually with perfective aspect especially in British English, to show that something has not happened by a particular time. yet comes at the end of a sentence:
It was late, but they hadn't arrived yet.
Have you fixed the car yet?
She won't have sent the email yet.