21.Apples are usually sold by weight and eggs are sometimes sold by dozen
A.the;the B./:a C./;the D.the;a
22.Although he sometimes loses his temper, his students like him for it.
A.not so much B.not so little
C.no more D.no less
23.一How about you paying for the fuel cost and me accommodation?
一 .I can’t wait for the trip.
A.It is a deal B.Don’t mention it
C.Never mind D.With pleasure
24. yesterday,we went out for a wall
A.As a fine day B.It was a fine day
C.It being a fine day D.For it was a fine day