English verb conjugation
MUST SNIFF

Regular verb: sniff - sniffed - sniffed

Affirmation

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

Negation

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

Interrogative form

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

Interro-negative form

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