Step-by-step explanation:
The verb in the present continuous tense is made of two parts:
The present tense form of verb ‘to be’ – is/am/are
‘ing’ affixed to the base verb.
Sentences in the present continuous form have a specified structure:
The affirmative sentence structure
subject + present tense form of verb ‘to be’ + base verb+ing
Example: She (subject)+ is (present tense form of ‘to be’)+ sing (base-verb)+ing ==> She is singing.
Negative sentence structure:
subject+ present tense form of verb ‘to be’ + not + base verb + ‘ing’
Example: She is not singing
Interrogative structure:
Present tense form of verb ‘to be’ + subject + base verb + ing + Question tag
Example: Is she singing?