could tip
Regular verb: tip - tipped- tipped

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could tip
you could tip
she could tip
we could tip
you could tip
they could tip 	I could be tipping
you could be tipping
she could be tipping
we could be tipping
you could be tipping
they could be tipping	I could have tipped
you could have tipped
she could have tipped
we could have tipped
you could have tipped
they could have tipped	I could have been tipping
you could have been tipping
she could have been tipping
we could have been tipping
you could have been tipping
they could have been tipping	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could not tip
you could not tip
she could not tip
we could not tip
you could not tip
they could not tip 	I could not be tipping
you could not be tipping
she could not be tipping
we could not be tipping
you could not be tipping
they could not be tipping	I could not have tipped
you could not have tipped
she could not have tipped
we could not have tipped
you could not have tipped
they could not have tipped	I could not have been tipping
you could not have been tipping
she could not have been tipping
we could not have been tipping
you could not have been tipping
they could not have been tipping	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I tip?
could you tip?
could she tip?
could we tip?
could you tip?
could they tip? 	could I be tipping?
could you be tipping?
could she be tipping?
could we be tipping?
could you be tipping?
could they be tipping? 	could I have tipped?
could you have tipped?
could she have tipped?
could we have tipped?
could you have tipped?
could they have tipped? 	could I have been tipping?
could you have been tipping?
could she have been tipping?
could we have been tipping?
could you have been tipping?
could they have been tipping? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I not tip?
could you not tip?
could she not tip?
could we not tip?
could you not tip?
could they not tip? 	could I not be tipping?
could you not be tipping?
could she not be tipping?
could we not be tipping?
could you not be tipping?
could they not be tipping? 	could I not have tipped?
could you not have tipped?
could she not have tipped?
could we not have tipped?
could you not have tipped?
could they not have tipped? 	could I not have been tipping?
could you not have been tipping?
could she not have been tipping?
could we not have been tipping?
could you not have been tipping?
could they not have been tipping?