If H2 burn in O2, we can get _____.
I can’t tell when that house ______ exactly, but it must be very long ago.
—Who’s singing in the next room?—It ____ be her. She has gone to New York.
—What about going skating this afternoon, Sam?—I would rather ______ at home than ______ skating on such a cold day.
—Where are your parents, Leo?—They are in Europe for shopping. They______ there for two weeks.
—What did the teacher ask you to do just now?—She said “Each student must ______ a composition once a week.”