(2014·北京海淀模拟)Only by improving education and high science technology can a country become a(n)________one.

After a careful survey about the cause of the newly-built bridge, they finally came to a(n) _________ that it was due to the heavy rain.

 Nowadays, teachers should give less homework to students in order to ______ the amount of pressure they have.

Don't worry about my illness. What I need is ________ but a few days' rest.

All the guests disliked the salted fish. They 　　　 this dish 　　　.