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.
library
suffer
– I don’t think I can go any further.– ______. You can do it if you keep trying!
– Do you mind if I smoke?– Well, I’d rather you ______.
Their youngest girl is at the stage ______ she can say a single word but not a full sentence