English verb conjugation
CAN OBSERVE

Regular verb: observe - observed - observed

Affirmation

Simple form	V-ing form
I can observe you can observe she can observe we can observe you can observe they can observe	I can be observing you can be observing she can be observing we can be observing you can be observing they can be observing
Perfect	V-ing perfect
I can have observed you can have observed she can have observed we can have observed you can have observed they can have observed	I can have been observing you can have been observing she can have been observing we can have been observing you can have been observing they can have been observing

Negation

Simple form	V-ing form
I cannot observe you cannot observe she cannot observe we cannot observe you cannot observe they cannot observe	I cannot be observing you cannot be observing she cannot be observing we cannot be observing you cannot be observing they cannot be observing
Perfect	V-ing perfect
I cannot have observed you cannot have observed she cannot have observed we cannot have observed you cannot have observed they cannot have observed	I cannot have been observing you cannot have been observing she cannot have been observing we cannot have been observing you cannot have been observing they cannot have been observing

Interrogative form

Simple form	V-ing form
can I observe? can you observe? can she observe? can we observe? can you observe? can they observe?	can I be observing? can you be observing? can she be observing? can we be observing? can you be observing? can they be observing?
Perfect	V-ing perfect
can I have observed? can you have observed? can she have observed? can we have observed? can you have observed? can they have observed?	can I have been observing? can you have been observing? can she have been observing? can we have been observing? can you have been observing? can they have been observing?

Interro-negative form

Simple form	V-ing form
can I not observe? can you not observe? can she not observe? can we not observe? can you not observe? can they not observe?	can I not be observing? can you not be observing? can she not be observing? can we not be observing? can you not be observing? can they not be observing?
Perfect	V-ing perfect
can I not have observed? can you not have observed? can she not have observed? can we not have observed? can you not have observed? can they not have observed?	can I not have been observing? can you not have been observing? can she not have been observing? can we not have been observing? can you not have been observing? can they not have been observing?