. Many people think that it is ____________making such an experiment.
| A．worthwhile | B．worth | C．worthy | D．valuable |
US President Barack Obama is expecting the economy to show some _________ of recovery．
| A．attempts | B．signs | C．contents | D．waves |
—She got her first science fiction published．It turned out to be _________.
—when was that?
—It Was in 2008__________ she was still in college．
| A．success; that | B．a success；when | C．success; when | D．a success; that |
He managed to reach the summit of his career, but it was at the _________ of his health.
| A．consumption | B．credit | C．exhaustion | D．expense |
As is well known, the brain performs a very important _______, which controls the nerve system of the body.
| A．motion | B．action | C．function | D．fact |
—Jack Brown is very clever and he studies hard as well.
—No ________ he comes out first in the exams.
| A．answer | B．question | C．wonder | D．problem |