I can drop you can drop he can drop we can drop you can drop they can drop
V-ing form
I can be dropping you can be dropping he can be dropping we can be dropping you can be dropping they can be dropping
Perfect
I can have dropped you can have dropped he can have dropped we can have dropped you can have dropped they can have dropped
V-ing perfect
I can have been dropping you can have been dropping he can have been dropping we can have been dropping you can have been dropping they can have been dropping
Negation
Simple form
I can't drop you can't drop he can't drop we can't drop you can't drop they can't drop
V-ing form
I can't be dropping you can't be dropping he can't be dropping we can't be dropping you can't be dropping they can't be dropping
Perfect
I can't have dropped you can't have dropped he can't have dropped we can't have dropped you can't have dropped they can't have dropped
V-ing perfect
I can't have been dropping you can't have been dropping he can't have been dropping we can't have been dropping you can't have been dropping they can't have been dropping
Interrogative form
Simple form
can I drop? can you drop? can he drop? can we drop? can you drop? can they drop?
V-ing form
can I be dropping? can you be dropping? can he be dropping? can we be dropping? can you be dropping? can they be dropping?
Perfect
can I have dropped? can you have dropped? can he have dropped? can we have dropped? can you have dropped? can they have dropped?
V-ing perfect
can I have been dropping? can you have been dropping? can he have been dropping? can we have been dropping? can you have been dropping? can they have been dropping?
Interro-negative form
Simple form
can't I drop? can't you drop? can't he drop? can't we drop? can't you drop? can't they drop?
V-ing form
can't I be dropping? can't you be dropping? can't he be dropping? can't we be dropping? can't you be dropping? can't they be dropping?
Perfect
can't I have dropped? can't you have dropped? can't he have dropped? can't we have dropped? can't you have dropped? can't they have dropped?
V-ing perfect
can't I have been dropping? can't you have been dropping? can't he have been dropping? can't we have been dropping? can't you have been dropping? can't they have been dropping?