The Olympic _____ remind us of where the Olympics are held and the characteristics of the host country.
| A．symbols | B．signals | C．marks | D．signs |
I received a letter，poor spelling made me think it was written by a child．
| A．which | B．that | C．whose | D．who |
The new online library makespossible for students to choose books by smart phone off campus．
| A．it | B．one | C．that | D．this |
We were delayed at the airport．Otherwise，wehere by lunch．
| A．must have been | B．could be |
| C．should be | D．would have been |
According to the latest study，most traffic accidentsbe prevented if drivers are careful enough．
| A．must | B．can | C．have to | D．need |
He never complains about the difficulties he has in life．，he always has ways to overcome them．
| A．However | B．Otherwise | C．Instead | D．Therefore |