could quake
Regular verb: quake - quaked- quaked

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could quake
you could quake
he could quake
we could quake
you could quake
they could quake 	I could be quaking
you could be quaking
he could be quaking
we could be quaking
you could be quaking
they could be quaking	I could have quaked
you could have quaked
he could have quaked
we could have quaked
you could have quaked
they could have quaked	I could have been quaking
you could have been quaking
he could have been quaking
we could have been quaking
you could have been quaking
they could have been quaking	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could not quake
you could not quake
he could not quake
we could not quake
you could not quake
they could not quake 	I could not be quaking
you could not be quaking
he could not be quaking
we could not be quaking
you could not be quaking
they could not be quaking	I could not have quaked
you could not have quaked
he could not have quaked
we could not have quaked
you could not have quaked
they could not have quaked	I could not have been quaking
you could not have been quaking
he could not have been quaking
we could not have been quaking
you could not have been quaking
they could not have been quaking	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I quake?
could you quake?
could he quake?
could we quake?
could you quake?
could they quake? 	could I be quaking?
could you be quaking?
could he be quaking?
could we be quaking?
could you be quaking?
could they be quaking? 	could I have quaked?
could you have quaked?
could he have quaked?
could we have quaked?
could you have quaked?
could they have quaked? 	could I have been quaking?
could you have been quaking?
could he have been quaking?
could we have been quaking?
could you have been quaking?
could they have been quaking? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I not quake?
could you not quake?
could he not quake?
could we not quake?
could you not quake?
could they not quake? 	could I not be quaking?
could you not be quaking?
could he not be quaking?
could we not be quaking?
could you not be quaking?
could they not be quaking? 	could I not have quaked?
could you not have quaked?
could he not have quaked?
could we not have quaked?
could you not have quaked?
could they not have quaked? 	could I not have been quaking?
could you not have been quaking?
could he not have been quaking?
could we not have been quaking?
could you not have been quaking?
could they not have been quaking?