______ I admit that all these problems are difficult, I don’t agree that they can’t be solved.
| A．Unless | B．While | C．Until | D．Since |
.
Water can absorb and _______ a lot of heat without big changes in temperature.
| A．give up | B．give out | C．give away | D．give off |
.
Han Han, a young writer, is famous _______ his novels.
| A．for | B．as | C．to | D．with |
.
Of all the works Stevenson has written, Treasure Island is probably his _______ work.
| A．well-known | B．more-known | C．most-known | D．best-known |
.
The reason for their failure, you know, was _______ they didn’t get fully prepared for it.
| A．why | B．whether | C．that | D．what |
.
. John promised his parents he _______ not smoke again, and he has not smoked ever since.
| A．would | B．could | C．should | D．might |