— What great trouble I have solving this problem now！
—_____ my advice, you ________less trouble.
| A．If you had taken, would have had | B．If you took, would have |
| C．If you had taken, would have | D．If you take, will have |
Police in America have stepped up their search for a fifteen-year-old boy who went _____ three days ago.
| A．going | B．losing |
| C．missing | D．disappearing |
There are _____ flights between the two cities, _____ it convenient for people in one city to travel to work in the other.
| A．regular; to make | B．usual; making |
| C．usual; having made | D．regular, making |
Though faced with so many difficulties, they are _____ about their future.
| A．curious | B．enthusiastic |
| C．optimistic | D．concerned |
The Sahara Desert is almost _____ of the US.
| A．as big | B．the size |
| C．the area | D．the same |
---It’s a long time since I saw Marry.
--- _________ her this afternoon?
| A．Why not to | B．Why not visit her |
| C．Why not visiting | D．Why don’t visit |