He is so addicted to smoking that ______ seems to be no chance of talking him into quitting.
—Did you enjoy yourself at the party? —Yes. I've never been to __________ one before.
He is very popular among his students as he always tries to make them __________ in his lectures.
My advisor encouraged __________ a summer course to improve my writing skills.
The policeman asked __________ with the old woman.
He speaks English well indeed, but of course not __________ a native speaker.