I can labour you can labour he can labour we can labour you can labour they can labour
V-ing form
I can be labouring you can be labouring he can be labouring we can be labouring you can be labouring they can be labouring
Perfect
I can have laboured you can have laboured he can have laboured we can have laboured you can have laboured they can have laboured
V-ing perfect
I can have been labouring you can have been labouring he can have been labouring we can have been labouring you can have been labouring they can have been labouring
Negation
Simple form
I cannot labour you cannot labour he cannot labour we cannot labour you cannot labour they cannot labour
V-ing form
I cannot be labouring you cannot be labouring he cannot be labouring we cannot be labouring you cannot be labouring they cannot be labouring
Perfect
I cannot have laboured you cannot have laboured he cannot have laboured we cannot have laboured you cannot have laboured they cannot have laboured
V-ing perfect
I cannot have been labouring you cannot have been labouring he cannot have been labouring we cannot have been labouring you cannot have been labouring they cannot have been labouring
Interrogative form
Simple form
can I labour? can you labour? can he labour? can we labour? can you labour? can they labour?
V-ing form
can I be labouring? can you be labouring? can he be labouring? can we be labouring? can you be labouring? can they be labouring?
Perfect
can I have laboured? can you have laboured? can he have laboured? can we have laboured? can you have laboured? can they have laboured?
V-ing perfect
can I have been labouring? can you have been labouring? can he have been labouring? can we have been labouring? can you have been labouring? can they have been labouring?
Interro-negative form
Simple form
can I not labour? can you not labour? can he not labour? can we not labour? can you not labour? can they not labour?
V-ing form
can I not be labouring? can you not be labouring? can he not be labouring? can we not be labouring? can you not be labouring? can they not be labouring?
Perfect
can I not have laboured? can you not have laboured? can he not have laboured? can we not have laboured? can you not have laboured? can they not have laboured?
V-ing perfect
can I not have been labouring? can you not have been labouring? can he not have been labouring? can we not have been labouring? can you not have been labouring? can they not have been labouring?