Conjugation of verb "To sing"
Present Simple Continuous
Negative
He/She/It wasn't singing.
Present Perfect Continuous
Affirmative
He/She/It's been singing.
Negative
You haven't been singing.
He/She/It hasn't been singing.
You haven't been singing.
They haven't been singing.
Interrogative
Has he/she/it been singing?
Affirmative
He/She/It'd been singing.
Negative
He/She/It hadn't been singing.
They hadn't been singing.
Interrogative
Had he/she/it been singing?
Negative
He/She/It won't have sung.
Interrogative
Will he/she/it have sung?
Negative
He/She/It wouldn't have sung.
Interrogative
Would he/she/it have sung?