25. The mechanism by which brain cells store memories is not clearly understood.
    大腦細胞儲存記憶的機理并不為人明白。

26. By the middle of the twentieth century, painters and sculptors in the United States had begun to exert a great worldwide influence over art.
    到了二十一世紀中葉，美國畫家和雕塑家開始在世界范圍內(nèi)對藝術(shù)產(chǎn)生重大影響。

27. In the eastern part of New Jersey lies the city of Elizabeth, a major shipping and manufacturing center.
    伊麗莎白市，一個重要的航運和制造業(yè)中心，坐落于新澤西州的東部。

28. Elizabeth Blackwell, the first woman medical doctor in the United States, founded the New York Infirmary, an institution that has always had a completely female medical staff.
    Elizabeth Blackwell，美國第一個女醫(yī)生，創(chuàng)建了員工一直為女性紐約診所。

29. Alexander Graham Bell once told his family that he would rather be remembered as a teacher of the deaf than as the inventor of the telephone.
     Alexander Graham Bell曾告訴家人，他更愿意讓后人記住他是聾子的老師，而非電話的發(fā)明者。

30. Because its leaves remain green long after being picked, rosemary became associated with the idea of remembrance.
    采摘下的迷迭香樹葉常綠不衰，因此人們把迷迭香樹與懷念聯(lián)系在一起。

31. Although apparently rigid, bones exhibit a degree of elasticity that enables the skeleton to withstand considerable impact.
    骨頭看起來是脆硬的，但它也有一定的彈性，使得骨骼能夠承受相當(dāng)?shù)拇驌簟?br />
32. That xenon could not FORM chemical compounds was once believed by scientists.
    科學(xué)家曾相信：氙氣是不能形成化合物的。