298. It has been laid down that each student must _____ a composition to the teacher once a week.

　A. turn in B. give up C. put forward D. bring out

297. Radium salts, which have been found to _____ in bones, give rise to cancers of the bone.

　A. pile up B. build up C. keep up D. pull up

296. Having said he would mend the clock, he discovered that he had not brought the _____ tools for the job.

　A. concise B. correct C. right D. precise

295.The country needs a _____ government. We have had three Prime Ministers in a year.

　stant D.stable

294. There is a 20 minute parking _____ here, so we must get back to the car very quickly.

　A. freedom B. limit C. allowance D. prohibition

293. Because of the poor harvest, wheat prices have _____ in the last six months.

　A. added B. jumped C. amounted D. developed

292. I can't advise you what to do. You must use your own _____.

　A. opinion B. guesswork C. justice D. judgment

291. Tell your brother to come _____, because it's going to rain in a minute or two.

　A. indoors B. outdoors C. outward D. inwards

290. A successful scientist needs _____ if he wants to make hypothesis (假设) of how processes work and how events take place.

　A. permission B. penetration C. imagination D. convention

289. This year the farmers were just able to gather in the _____ before the fine weather came to an end.

　A. collection B. harvest C. flower D. plant