English verb conjugation
CAN SNIFF

Regular verb: sniff - sniffed - sniffed

Affirmation

Simple form	V-ing form
I can sniff you can sniff he can sniff we can sniff you can sniff they can sniff	I can be sniffing you can be sniffing he can be sniffing we can be sniffing you can be sniffing they can be sniffing
Perfect	V-ing perfect
I can have sniffed you can have sniffed he can have sniffed we can have sniffed you can have sniffed they can have sniffed	I can have been sniffing you can have been sniffing he can have been sniffing we can have been sniffing you can have been sniffing they can have been sniffing

Negation

Simple form	V-ing form
I can't sniff you can't sniff he can't sniff we can't sniff you can't sniff they can't sniff	I can't be sniffing you can't be sniffing he can't be sniffing we can't be sniffing you can't be sniffing they can't be sniffing
Perfect	V-ing perfect
I can't have sniffed you can't have sniffed he can't have sniffed we can't have sniffed you can't have sniffed they can't have sniffed	I can't have been sniffing you can't have been sniffing he can't have been sniffing we can't have been sniffing you can't have been sniffing they can't have been sniffing

Interrogative form

Simple form	V-ing form
can I sniff? can you sniff? can he sniff? can we sniff? can you sniff? can they sniff?	can I be sniffing? can you be sniffing? can he be sniffing? can we be sniffing? can you be sniffing? can they be sniffing?
Perfect	V-ing perfect
can I have sniffed? can you have sniffed? can he have sniffed? can we have sniffed? can you have sniffed? can they have sniffed?	can I have been sniffing? can you have been sniffing? can he have been sniffing? can we have been sniffing? can you have been sniffing? can they have been sniffing?

Interro-negative form

Simple form	V-ing form
can't I sniff? can't you sniff? can't he sniff? can't we sniff? can't you sniff? can't they sniff?	can't I be sniffing? can't you be sniffing? can't he be sniffing? can't we be sniffing? can't you be sniffing? can't they be sniffing?
Perfect	V-ing perfect
can't I have sniffed? can't you have sniffed? can't he have sniffed? can't we have sniffed? can't you have sniffed? can't they have sniffed?	can't I have been sniffing? can't you have been sniffing? can't he have been sniffing? can't we have been sniffing? can't you have been sniffing? can't they have been sniffing?