Sentence is in present perfect continuous tense.
Rule :
Subject + have/has + been + V-ing + other agents.
I have been teaching English online since July, 2014.

I am also your friend. Would you invite me in your birthday celebration?

I am in boys' hostel now.

In such sentences starting with "If" we generally use a positive sentence before the comma because the second part of the sentence is in negative.
If I had a lot of money, I wouldn't work anymore.

Few is a quantifier used with plural countable nouns. Little is used with singular uncountable nouns. Friends are plural countable nouns. 'a few' means some. Option B is correct.
If you have a few good friends in life, life is worth living.

When you are speaking of or for yourself, use "am." When you are talking about a person or a thing (in the singular), use "is." When you are talking to a person, and when you are talking about other people or things (in the plural), use "are."
He and she are watching a movie now.

Few is a quantifier used with plural countable nouns. Little is used with singular uncountable nouns. Minutes are plural countable nouns. Option A is correct.
He didn’t wait even few minutes but started a lecture.

Few is a quantifier used with plural countable nouns. Little is used with singular uncountable nouns. Love is singular uncountable noun.
Have a little love for animals.

Few is a quantifier used with plural countable nouns. Little is used with singular uncountable nouns. Juice is singular uncountable noun.
Give me a little mango juice.

He or she is watching a movie now.

"Reminds of" someone.
He reminds us of Paul Walker.

How can you solve this puzzle?

die of (disease): He died of cholera.
die from (effect ): He died from snake bite/ over eating.
die for (shake / cause): He died for his country .
die by ( accident): He died by an accident.
die in ( place / month / year): He died in 1950./ He died in London. / He died in a hospital in Dhaka.
die in (accident ): He died in a train accident.
die on ( name of day /spot death): He died on the spot./ He died on Monday.
die at( time): He died at 9–30 a m.
die between ( time): He died between 9 a m to 9–30 a m.
die within (time ): He died within five minutes.

That child died of heavy fever.

Put off --- to rid oneself of, take off.
I put off my hat when I come home.

Why isn't David going to the party?

Few is a quantifier used with plural countable nouns. Little is used with singular uncountable nouns. Hope is singular uncountable nouns. Option C is correct.
He has been seriously injured. There is little hope for his survival.

"May" is used when someone has to ask for something from someone because it sounds polite.
May I come in, sir?

If I were the richest person of the world!

By using "took" a simple past tense sentence can be made. Other options make a grammatically incorrect sentence.
In olden days, doves took messages.

The preposition that goes with "fond" is "of".
Kishan sir is very much fond of teaching English.

He divided his property between his two sons.
When there is more than two person, we use 'among'.

He has many female friends.

He is very weak. He cannot walk more.

Few is a quantifier used with plural countable nouns. Little is used with singular uncountable nouns. Mango is plural countable noun.
There are a few mangoes in a fridge. You can take any of them.

Few is a quantifier used with plural countable nouns. Little is used with singular uncountable nouns. Money is singular uncountable noun.
I have a little money. I will hire a rickshaw.

How many friends does she have?

Sentence is in present continuous tense.
Rule :
Subject + is/am/are + V-ing + other agents.
How many kites are flying in the sky now?

You, your, yours, yourself all of this are used in direct speech. He, his, her, they, their etc are used in indirect speech.
Follow the principle, “Do it yourself .”

Where did the family members go yesterday?

Ours is a very regular class, sir.