—I think I will recommend David as the chairperson of the club because he is        .—I quite agree with you. He is always willing to share his things with others.

At first, we didn’t know _______to do.

I don’t like this shirt. Could you show me ________ one?

─          did you play the piano today?    ─ For five hours.

Never visit strange websites, ________ the thieves may crack(破译)the password of your Internet account.