The present continuous tense indicates the continuity of an action which is going on at the present moment.

Form: Subject + is/are/am + -ing form of the verb.

I am doing sums.
We are looking at the black-board.
They were playing with the toys.
She is writing a letter to her friend.
They are waiting for us?
They are going to the market.

An interrogative sentence in the present continuous tense has the following structure.

Is/am/are + subject + -ing form of the verb.

Am I doing sums?
Are we looking at the black-board?
Were they playing with the toys?
Are you coming with us?
Is she writing a letter to her friend?
Are they waiting for us?
Are they going to the market?

Present perfect tense

The present perfect tense indicates the completion of an action. It has the following form:

Subject + has/have + past participle form of the verb.

They have arrived.
We have finished the job.
The workers have painted the house.
He has stolen my purse.
We have paid our dues.
We have learnt our lesson.
The sun has risen.

An interrogative sentence in the present perfect tense has the following structure.

Has/have + subject + past participle form of the verb

Have they arrived?
Have we finished the job?
Have the workers painted the house?
Has he stolen my purse?
Have we paid our dues?
Have we learnt our lesson?
Has the sun risen?

Present perfect continuous tense

The present perfect continuous tense has the following structure:

Subject + has/have + been + -ing form of the verb

She has been sleeping since morning.
He has been waiting for them for several hours.
We have been working hard for the examination for several months.
He has been doing this work for hours.
It has been raining heavily since the last night.

An interrogative sentence in the present perfect continuous tense has the following structure:

Has/have + subject + been + -ing form of the verb

Has she been sleeping since morning?
Has he been waiting for them for several hours?
Have we been working hard for the examination for several months?
Has he been doing this work for hours?
Has it been raining heavily since the last night?