could strain
Regular verb: strain - strained- strained

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could strain
you could strain
she could strain
we could strain
you could strain
they could strain 	I could be straining
you could be straining
she could be straining
we could be straining
you could be straining
they could be straining	I could have strained
you could have strained
she could have strained
we could have strained
you could have strained
they could have strained	I could have been straining
you could have been straining
she could have been straining
we could have been straining
you could have been straining
they could have been straining	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't strain
you couldn't strain
she couldn't strain
we couldn't strain
you couldn't strain
they couldn't strain 	I couldn't be straining
you couldn't be straining
she couldn't be straining
we couldn't be straining
you couldn't be straining
they couldn't be straining	I couldn't have strained
you couldn't have strained
she couldn't have strained
we couldn't have strained
you couldn't have strained
they couldn't have strained	I couldn't have been straining
you couldn't have been straining
she couldn't have been straining
we couldn't have been straining
you couldn't have been straining
they couldn't have been straining	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I strain?
could you strain?
could she strain?
could we strain?
could you strain?
could they strain? 	could I be straining?
could you be straining?
could she be straining?
could we be straining?
could you be straining?
could they be straining? 	could I have strained?
could you have strained?
could she have strained?
could we have strained?
could you have strained?
could they have strained? 	could I have been straining?
could you have been straining?
could she have been straining?
could we have been straining?
could you have been straining?
could they have been straining? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I strain?
couldn't you strain?
couldn't she strain?
couldn't we strain?
couldn't you strain?
couldn't they strain? 	couldn't I be straining?
couldn't you be straining?
couldn't she be straining?
couldn't we be straining?
couldn't you be straining?
couldn't they be straining? 	couldn't I have strained?
couldn't you have strained?
couldn't she have strained?
couldn't we have strained?
couldn't you have strained?
couldn't they have strained? 	couldn't I have been straining?
couldn't you have been straining?
couldn't she have been straining?
couldn't we have been straining?
couldn't you have been straining?
couldn't they have been straining?