I can extemporise you can extemporise he can extemporise we can extemporise you can extemporise they can extemporise
V-ing form
I can be extemporising you can be extemporising he can be extemporising we can be extemporising you can be extemporising they can be extemporising
Perfect
I can have extemporised you can have extemporised he can have extemporised we can have extemporised you can have extemporised they can have extemporised
V-ing perfect
I can have been extemporising you can have been extemporising he can have been extemporising we can have been extemporising you can have been extemporising they can have been extemporising
Negation
Simple form
I can't extemporise you can't extemporise he can't extemporise we can't extemporise you can't extemporise they can't extemporise
V-ing form
I can't be extemporising you can't be extemporising he can't be extemporising we can't be extemporising you can't be extemporising they can't be extemporising
Perfect
I can't have extemporised you can't have extemporised he can't have extemporised we can't have extemporised you can't have extemporised they can't have extemporised
V-ing perfect
I can't have been extemporising you can't have been extemporising he can't have been extemporising we can't have been extemporising you can't have been extemporising they can't have been extemporising
Interrogative form
Simple form
can I extemporise? can you extemporise? can he extemporise? can we extemporise? can you extemporise? can they extemporise?
V-ing form
can I be extemporising? can you be extemporising? can he be extemporising? can we be extemporising? can you be extemporising? can they be extemporising?
Perfect
can I have extemporised? can you have extemporised? can he have extemporised? can we have extemporised? can you have extemporised? can they have extemporised?
V-ing perfect
can I have been extemporising? can you have been extemporising? can he have been extemporising? can we have been extemporising? can you have been extemporising? can they have been extemporising?
Interro-negative form
Simple form
can't I extemporise? can't you extemporise? can't he extemporise? can't we extemporise? can't you extemporise? can't they extemporise?
V-ing form
can't I be extemporising? can't you be extemporising? can't he be extemporising? can't we be extemporising? can't you be extemporising? can't they be extemporising?
Perfect
can't I have extemporised? can't you have extemporised? can't he have extemporised? can't we have extemporised? can't you have extemporised? can't they have extemporised?
V-ing perfect
can't I have been extemporising? can't you have been extemporising? can't he have been extemporising? can't we have been extemporising? can't you have been extemporising? can't they have been extemporising?