Wah How to use It's about time.

We know how to use It's time but it's different than It's about time.
We use It's (about) time + Past tense to talk about something you should have done in the past but you didn't do it in that time. (It is almost too late.)

• It's about time he got a haircut. (Your hair is too long. You should have cut it 3 weeks ago, then you should get a haircut now.)
• It's about time you paid me. (It's 2 month late and you haven't paid me so far, you should pay me right now.)
• It's about time I started learning English.
• It's about time we had a break.
• It's about time you cleaned your shoes.

Note: We don't have to put about in the sentences
          It's time he got a haircut. 
          It's time we had a break.

Let's see the difference between It's time and It's about time.

• It's time for you to wash your car. (Your car is a bit dirty, you should wash it right now.)
• It's about time you washed your car. (Your car is very dirty. You should have washed it last week ago, then you should wash it right now.)

It's about time you get some new clothes.

Wah How to use Before and After with Gerund.

We can use Before and After with Subject + Verb or Gerund.

With Subject + Verb
    I went to the U.S. after I left school.

With Gerund
    I went to the U.S. after leaving school.

Note: Both of them have the same meaning as long as the subject is the same.

    Before Jason gets to work, he always buys a milkshake. 
    Before getting to work, Jason always buys a milkshake.

    After I decided, I started to worry about my decision. 
    After deciding, I started to worry about my decision. 

    Before you went to Maldives, how did you prepare? 
    Before going to Maldives, how did you prepare? 

    After you watch a good movie, what would you like to do? 
    After watching a good movie, what would you like to do? 

    Before John became a millionaire, he never enjoyed his life.
    Before becoming a millionaire, John never enjoyed his life.

Please turn all the lights off before leaving.

Wah How to use adverbs of frequency.

We use some adverbs to describe how frequently we do an activity.

These are called adverbs of frequency :

100% = always

75%   = often/frequently

50%   = sometimes

25%   = occasionally

5%     = hardly ever, rarely

0%     = never

• The actress always wears expensive jewels.
• The teacher has always been easy to consult with.
• I often go to the gym in the evening.
• They frequently go to the cinema together.
• I sometimes eat vegetables and fruits.
• He sometimes reads the newspaper.
• I occasionally drink alcohol.
• We occasionally have a dinner together.
• He hardly (ever) visit me.
• It hardly (ever) rains in this area.
• Our meeting rarely starts on time.
• I never climb the mountain.
• You will never walk alone :)

Note: We can use hardly to indicate a minimal level of ability of an action.
    I hardly hear you, what was that?
    You have changed so much that I can hardly recognize you.
    I hardly know how to do it.

Where can we put these adverbs in a sentence?

Wah How to use "A While".

A while = A short time.
So if we say "I will be there in a while", it means "I will be there in a short time".

The opposite of a while would be a long time.

We can use a short while to emphasize the short period of time.

• It is impossible to master English in a while. (It is impossible to master English in a short time.)
• The system will go into operation in a short while. (The system will go into operation in a short time.)
• I'll wait here for a while. (I'll wait here for a short time.)
• Would you mind if I watch TV for a while?
• Let's sit here for a while and look at the view.
• Please stay out of my way for a short while.  
• This machine is out of order for a short while.
• Leave me alone for a short while. It's none of your business.

Wah How to use "The last time"

We use The last time + past tense when we talk about the last time that someone do something or the last time that something happened.
We use this form when we want to emphasize the sentence.

    The last time I saw you was last year. (= I saw you last year. )
    The last time I see you is last year. is incorrect. 
    The last time I worked out was 4 months ago.(= I haven't worked out for 4 months. )
    The last time I took a trip in the U.S. was 3 years ago.
    The last time we went swimming was the summer.

    A: What was the last time you went shopping?
    B: The last time I went shopping was 3 weeks ago.

    A: What was your last time you saw the movies?
    B: The last time I saw the movies was in September.

The last time I saw you was 365 days ago.

Wah How to use "Once, Twice, Three Times..."

If you want to say how often you do something, You can use...

    one time (once)
    two times (twice)
    three times
    four times
    five times, etc.

       Q: How many times a week do you go to the movies?
       A: I usually go to the movies twice a week. 

       Q: How often do you wash your hair?
       A: I wash my hair three times a week.

       Q: How often do you eat raw fish?
       A: I eat raw fish once a week.

You might hear the word once upon a time.
    According to OED, once upon a time means at some time in the past (used as a conventional opening of a story). 

What about a long time ago?
    It means a long time ago in the past. Now, they could be used interchangeably in some cases, but once upon time could refer to something that happened a few days or a month ago, which is not long time ago, while the other couldn't.