49.Whether you live to eat or eat to live, food is a major _______ in every familys budget.

　　A.nutrition

　　B.expenditure 花費 費用

　　C.routine 例行公事 常規

　　D.provision 供應量

　　50.Now a paper in Science argues that organic chemicals in the rock come mostly from __________ on earth rather than bacteria on Mars

　　A.configuration 結構 分布形狀

　　B.constitution 憲法 事物的一般結構

　　C.condemnation 批評 責難

　　D.contamination 化學污染 放射性污染

　　51.There is much I enjoy about the changing seasons, but my favorite time is the ________ from fall to winter.

　　A.transmission

　　B.transformation 轉變

　　C.transition

　　D.transfer