1.All the second-hand goods are sold at_____before

1.All the second-hand goods are sold at_____before
A.twice as lower price as B.as twice low price than
C.twice as low a price as D.twice lower price than
2.the way i told him to try ____ almost the first time he had the chance to use it.
A.working B to work
c worked D had worked
3.It was _____i met Mr.Green in Shanghai
A ten years since B many years ago that
C five years until D two months than
4.this stadium has _____many thrilling football games
A seen B watched
c looked at D experienced