English verb conjugation
COULD STERILISE

Regular verb: sterilise - sterilised - sterilised

Affirmation

Simple form	V-ing form
I could sterilise you could sterilise he could sterilise we could sterilise you could sterilise they could sterilise	I could be sterilising you could be sterilising he could be sterilising we could be sterilising you could be sterilising they could be sterilising
Perfect	V-ing perfect
I could have sterilised you could have sterilised he could have sterilised we could have sterilised you could have sterilised they could have sterilised	I could have been sterilising you could have been sterilising he could have been sterilising we could have been sterilising you could have been sterilising they could have been sterilising

Negation

Simple form	V-ing form
I couldn't sterilise you couldn't sterilise he couldn't sterilise we couldn't sterilise you couldn't sterilise they couldn't sterilise	I couldn't be sterilising you couldn't be sterilising he couldn't be sterilising we couldn't be sterilising you couldn't be sterilising they couldn't be sterilising
Perfect	V-ing perfect
I couldn't have sterilised you couldn't have sterilised he couldn't have sterilised we couldn't have sterilised you couldn't have sterilised they couldn't have sterilised	I couldn't have been sterilising you couldn't have been sterilising he couldn't have been sterilising we couldn't have been sterilising you couldn't have been sterilising they couldn't have been sterilising

Interrogative form

Simple form	V-ing form
could I sterilise? could you sterilise? could he sterilise? could we sterilise? could you sterilise? could they sterilise?	could I be sterilising? could you be sterilising? could he be sterilising? could we be sterilising? could you be sterilising? could they be sterilising?
Perfect	V-ing perfect
could I have sterilised? could you have sterilised? could he have sterilised? could we have sterilised? could you have sterilised? could they have sterilised?	could I have been sterilising? could you have been sterilising? could he have been sterilising? could we have been sterilising? could you have been sterilising? could they have been sterilising?

Interro-negative form

Simple form	V-ing form
couldn't I sterilise? couldn't you sterilise? couldn't he sterilise? couldn't we sterilise? couldn't you sterilise? couldn't they sterilise?	couldn't I be sterilising? couldn't you be sterilising? couldn't he be sterilising? couldn't we be sterilising? couldn't you be sterilising? couldn't they be sterilising?
Perfect	V-ing perfect
couldn't I have sterilised? couldn't you have sterilised? couldn't he have sterilised? couldn't we have sterilised? couldn't you have sterilised? couldn't they have sterilised?	couldn't I have been sterilising? couldn't you have been sterilising? couldn't he have been sterilising? couldn't we have been sterilising? couldn't you have been sterilising? couldn't they have been sterilising?