English verb conjugation
COULD ENTER

Regular verb: enter - entered - entered

Affirmation

Simple form	V-ing form
I could enter you could enter he could enter we could enter you could enter they could enter	I could be entering you could be entering he could be entering we could be entering you could be entering they could be entering
Perfect	V-ing perfect
I could have entered you could have entered he could have entered we could have entered you could have entered they could have entered	I could have been entering you could have been entering he could have been entering we could have been entering you could have been entering they could have been entering

Negation

Simple form	V-ing form
I could not enter you could not enter he could not enter we could not enter you could not enter they could not enter	I could not be entering you could not be entering he could not be entering we could not be entering you could not be entering they could not be entering
Perfect	V-ing perfect
I could not have entered you could not have entered he could not have entered we could not have entered you could not have entered they could not have entered	I could not have been entering you could not have been entering he could not have been entering we could not have been entering you could not have been entering they could not have been entering

Interrogative form

Simple form	V-ing form
could I enter? could you enter? could he enter? could we enter? could you enter? could they enter?	could I be entering? could you be entering? could he be entering? could we be entering? could you be entering? could they be entering?
Perfect	V-ing perfect
could I have entered? could you have entered? could he have entered? could we have entered? could you have entered? could they have entered?	could I have been entering? could you have been entering? could he have been entering? could we have been entering? could you have been entering? could they have been entering?

Interro-negative form

Simple form	V-ing form
could I not enter? could you not enter? could he not enter? could we not enter? could you not enter? could they not enter?	could I not be entering? could you not be entering? could he not be entering? could we not be entering? could you not be entering? could they not be entering?
Perfect	V-ing perfect
could I not have entered? could you not have entered? could he not have entered? could we not have entered? could you not have entered? could they not have entered?	could I not have been entering? could you not have been entering? could he not have been entering? could we not have been entering? could you not have been entering? could they not have been entering?