I can crackle you can crackle he can crackle we can crackle you can crackle they can crackle
V-ing form
I can be crackling you can be crackling he can be crackling we can be crackling you can be crackling they can be crackling
Perfect
I can have crackled you can have crackled he can have crackled we can have crackled you can have crackled they can have crackled
V-ing perfect
I can have been crackling you can have been crackling he can have been crackling we can have been crackling you can have been crackling they can have been crackling
Negation
Simple form
I cannot crackle you cannot crackle he cannot crackle we cannot crackle you cannot crackle they cannot crackle
V-ing form
I cannot be crackling you cannot be crackling he cannot be crackling we cannot be crackling you cannot be crackling they cannot be crackling
Perfect
I cannot have crackled you cannot have crackled he cannot have crackled we cannot have crackled you cannot have crackled they cannot have crackled
V-ing perfect
I cannot have been crackling you cannot have been crackling he cannot have been crackling we cannot have been crackling you cannot have been crackling they cannot have been crackling
Interrogative form
Simple form
can I crackle? can you crackle? can he crackle? can we crackle? can you crackle? can they crackle?
V-ing form
can I be crackling? can you be crackling? can he be crackling? can we be crackling? can you be crackling? can they be crackling?
Perfect
can I have crackled? can you have crackled? can he have crackled? can we have crackled? can you have crackled? can they have crackled?
V-ing perfect
can I have been crackling? can you have been crackling? can he have been crackling? can we have been crackling? can you have been crackling? can they have been crackling?
Interro-negative form
Simple form
can I not crackle? can you not crackle? can he not crackle? can we not crackle? can you not crackle? can they not crackle?
V-ing form
can I not be crackling? can you not be crackling? can he not be crackling? can we not be crackling? can you not be crackling? can they not be crackling?
Perfect
can I not have crackled? can you not have crackled? can he not have crackled? can we not have crackled? can you not have crackled? can they not have crackled?
V-ing perfect
can I not have been crackling? can you not have been crackling? can he not have been crackling? can we not have been crackling? can you not have been crackling? can they not have been crackling?