could strain
Regular verb: strain - strained- strained

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could strain
you could strain
he could strain
we could strain
you could strain
they could strain 	I could be straining
you could be straining
he could be straining
we could be straining
you could be straining
they could be straining	I could have strained
you could have strained
he 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
he 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 could not strain
you could not strain
he could not strain
we could not strain
you could not strain
they could not strain 	I could not be straining
you could not be straining
he could not be straining
we could not be straining
you could not be straining
they could not be straining	I could not have strained
you could not have strained
he could not have strained
we could not have strained
you could not have strained
they could not have strained	I could not have been straining
you could not have been straining
he could not have been straining
we could not have been straining
you could not have been straining
they could not have been straining	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I strain?
could you strain?
could he strain?
could we strain?
could you strain?
could they strain? 	could I be straining?
could you be straining?
could he be straining?
could we be straining?
could you be straining?
could they be straining? 	could I have strained?
could you have strained?
could he 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 he 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 	
could I not strain?
could you not strain?
could he not strain?
could we not strain?
could you not strain?
could they not strain? 	could I not be straining?
could you not be straining?
could he not be straining?
could we not be straining?
could you not be straining?
could they not be straining? 	could I not have strained?
could you not have strained?
could he not have strained?
could we not have strained?
could you not have strained?
could they not have strained? 	could I not have been straining?
could you not have been straining?
could he not have been straining?
could we not have been straining?
could you not have been straining?
could they not have been straining?