English verb conjugation
CAN SIP

Regular verb: sip - sipped - sipped

Affirmation

Simple form	V-ing form
I can sip you can sip he can sip we can sip you can sip they can sip	I can be sipping you can be sipping he can be sipping we can be sipping you can be sipping they can be sipping
Perfect	V-ing perfect
I can have sipped you can have sipped he can have sipped we can have sipped you can have sipped they can have sipped	I can have been sipping you can have been sipping he can have been sipping we can have been sipping you can have been sipping they can have been sipping

Negation

Simple form	V-ing form
I cannot sip you cannot sip he cannot sip we cannot sip you cannot sip they cannot sip	I cannot be sipping you cannot be sipping he cannot be sipping we cannot be sipping you cannot be sipping they cannot be sipping
Perfect	V-ing perfect
I cannot have sipped you cannot have sipped he cannot have sipped we cannot have sipped you cannot have sipped they cannot have sipped	I cannot have been sipping you cannot have been sipping he cannot have been sipping we cannot have been sipping you cannot have been sipping they cannot have been sipping

Interrogative form

Simple form	V-ing form
can I sip? can you sip? can he sip? can we sip? can you sip? can they sip?	can I be sipping? can you be sipping? can he be sipping? can we be sipping? can you be sipping? can they be sipping?
Perfect	V-ing perfect
can I have sipped? can you have sipped? can he have sipped? can we have sipped? can you have sipped? can they have sipped?	can I have been sipping? can you have been sipping? can he have been sipping? can we have been sipping? can you have been sipping? can they have been sipping?

Interro-negative form

Simple form	V-ing form
can I not sip? can you not sip? can he not sip? can we not sip? can you not sip? can they not sip?	can I not be sipping? can you not be sipping? can he not be sipping? can we not be sipping? can you not be sipping? can they not be sipping?
Perfect	V-ing perfect
can I not have sipped? can you not have sipped? can he not have sipped? can we not have sipped? can you not have sipped? can they not have sipped?	can I not have been sipping? can you not have been sipping? can he not have been sipping? can we not have been sipping? can you not have been sipping? can they not have been sipping?