---Why do you look so upset?
---There are so many troublesome problems ____.
| A．remaining to be settled | B．remained settled |
| C．remaining to settle | D．remained to be settled |
As we all know, ______ knowledge comes from _______ practice.
| A．the; the | B．a; a | C．the ;× | D．×; × |
We should prevent pollution ________ happily.
| A．to live | B．for living | C．from living | D．living |
The line is engaged. I can’t _____ now.
| A．get on | B．get along | C．get through | D．get down |
It had rained for several days. The clothes had _____ near the fire to dry.
| A．hang up | B．to hung up | C．to be hung up | D．to be hanged up |
This kind of paper was as soft and light as silk but ______ expensive.
| A．much less | B．much little | C．many less | D．much more than |