Swimmers must be very strong in order to build up speed because of the high resistance (阻力)of the water. Runners,__________, must struggle against the heavy resistance of the air and ground.
I like these English songs and they ________ many times on the radio.
—Did you watch the basketball match yesterday?—Yes,I did.You know,my brother ________ in the match.
—I'd like a pen which ________ well.—Will this one ________?
I like getting up very early in summer.The morning air is so good ________.
Professor Williams keeps telling his students that the future ________to the well-educated.