This is the question part of the present continuous tense.
The present continuous tense indicates an ongoing action or state of existence. The present continuous tense indicates that the time when the action occurs is "now" and the current status of the action is "in progress". The so-called "in progress" means that when talking about this matter, the action is still in progress. 1. The action that is happening at the moment when you are speaking or writing the article. 2. The action that is ongoing at this stage.
◇what are they doing? , They are playing basketball now.
What are they doing? Now, they are playing basketball.
◇Listen, She is singing an English song.
Listen, she is singing an English song.
◇Look at the picture. The children are flying kites in the park.
Look at the picture. The children were flying kites in the park.
◇We are making model planes these days.
We are making model planes these days.
Composition
The composition of the present continuous tense is: subject + be verb + verb ing form [present participle]
Affirmative sentence: subject + be verb + verb ing+other.
Negative sentence: subject + be verb + not + verb ing + other.
General questions: Be verb + subject + verb ing + others.
Affirmative answer: Yes, subject + be verb.
Negative answer: No, subject + be verb + not.
Note: is not can be abbreviated to isn't, are not can be abbreviated to aren't, but am not cannot be abbreviated in modern English - in ancient English and poetry am not is abbreviated to ain' t.