I can buckle you can buckle he can buckle we can buckle you can buckle they can buckle
V-ing form
I can be buckling you can be buckling he can be buckling we can be buckling you can be buckling they can be buckling
Perfect
I can have buckled you can have buckled he can have buckled we can have buckled you can have buckled they can have buckled
V-ing perfect
I can have been buckling you can have been buckling he can have been buckling we can have been buckling you can have been buckling they can have been buckling
Negation
Simple form
I can't buckle you can't buckle he can't buckle we can't buckle you can't buckle they can't buckle
V-ing form
I can't be buckling you can't be buckling he can't be buckling we can't be buckling you can't be buckling they can't be buckling
Perfect
I can't have buckled you can't have buckled he can't have buckled we can't have buckled you can't have buckled they can't have buckled
V-ing perfect
I can't have been buckling you can't have been buckling he can't have been buckling we can't have been buckling you can't have been buckling they can't have been buckling
Interrogative form
Simple form
can I buckle? can you buckle? can he buckle? can we buckle? can you buckle? can they buckle?
V-ing form
can I be buckling? can you be buckling? can he be buckling? can we be buckling? can you be buckling? can they be buckling?
Perfect
can I have buckled? can you have buckled? can he have buckled? can we have buckled? can you have buckled? can they have buckled?
V-ing perfect
can I have been buckling? can you have been buckling? can he have been buckling? can we have been buckling? can you have been buckling? can they have been buckling?
Interro-negative form
Simple form
can't I buckle? can't you buckle? can't he buckle? can't we buckle? can't you buckle? can't they buckle?
V-ing form
can't I be buckling? can't you be buckling? can't he be buckling? can't we be buckling? can't you be buckling? can't they be buckling?
Perfect
can't I have buckled? can't you have buckled? can't he have buckled? can't we have buckled? can't you have buckled? can't they have buckled?
V-ing perfect
can't I have been buckling? can't you have been buckling? can't he have been buckling? can't we have been buckling? can't you have been buckling? can't they have been buckling?