It’s good       us       walk after supper every day.

We never        how to open the box.

—What do you usually do in your spare time, playing the violin or the piano?—I do        of them. I practice singing with some volunteers.

       human beings        animals can live without air.

—I haven’t had my breakfast.—      I.

—      the population of Hong Kong?—Seven million people.

—How long        you        this bicycle?—For two years.

—Where is your uncle? —He      London. He       there once before.

I have been here      .

—How clean the bedroom is! —Yes. I am sure that someone     it.