Irregular Verbs

Below are some examples of the basic tenses that are used with irregular verbs, such as drink, sing and swim.
These are the forms of the main verb that we use to construct the tenses:

base verb	past	past participle	present participle – ing
swim	swam	swum	swimming

 

		past	present	future
SIMPLE do + base verb (except future: will + base verb)	+	She did swim. She swam.	She does swim. She swims.	She will swim.
	–	She didn’t swim.	She does not swim.	She will not swim.
	?	Did she swim?	Do you swim?	Will you swim?
SIMPLE PERFECT have + past participle	+	I had swum.	I have swum.	I will have swum.
	–	She had not swum.	She has not swum.	She will not have swum.
	?	Had she swum?	Has she swum?	Will she have swum?
CONTINUOUS be + ing	+	She was swimming.	She is swimming.	She will be swimming.
	–	She was not swimming.	She is not swimming.	She will not be swimming.
	?	Was she swimming?	Is she swimming?	Will she be swimming?
CONTINUOUS PERFECT have been + –ing	+	She had been swimming.	She has been swimming.	She will have been swimming.
	–	She had not been swimming.	She has not been swimming.	She will not have been swimming.
	?	Had she been swimming?	Has she been swimming?	Will she have been swimming?

The difference between regular and irregular verb tenses is that regular verbs, such as play are always the same.
For example:
play, played, playing

Irregular verbs such as sing use different words all together to refer to tense.
For example:
sing, sang, sung, singing.