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 cannot extemporise you cannot extemporise he cannot extemporise we cannot extemporise you cannot extemporise they cannot extemporise
V-ing form
I cannot be extemporising you cannot be extemporising he cannot be extemporising we cannot be extemporising you cannot be extemporising they cannot be extemporising
Perfect
I cannot have extemporised you cannot have extemporised he cannot have extemporised we cannot have extemporised you cannot have extemporised they cannot have extemporised
V-ing perfect
I cannot have been extemporising you cannot have been extemporising he cannot have been extemporising we cannot have been extemporising you cannot have been extemporising they cannot 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 I not extemporise? can you not extemporise? can he not extemporise? can we not extemporise? can you not extemporise? can they not extemporise?
V-ing form
can I not be extemporising? can you not be extemporising? can he not be extemporising? can we not be extemporising? can you not be extemporising? can they not be extemporising?
Perfect
can I not have extemporised? can you not have extemporised? can he not have extemporised? can we not have extemporised? can you not have extemporised? can they not have extemporised?
V-ing perfect
can I not have been extemporising? can you not have been extemporising? can he not have been extemporising? can we not have been extemporising? can you not have been extemporising? can they not have been extemporising?