1、That xenon could not form chemical compounds was once believed by scientists.
[参考译文]科学家曾相信：氙气是不能形成化合物的。
2、153、Although apparently rigid（坚硬的）, bones exhibit a degree of elasticity（弹力，弹性） that enables the skeleton to withstand （承受）considerable impact（冲撞）.
[参考译文]骨头看起来是脆硬的，但它也有一定的弹性，使得骨骼能够承受相当的打击。
3、Not until 1866 was the fully successful transatlantic cable finally laid.
[参考译文]直到1866年第一条横跨大西洋的电缆才完全成功的架通。
4、According to anthropologists, the earliest ancestors of humans that stood upright resembled chimpanzees（黑猩猩） facially, with sloping（倾斜的） foreheads and protruding（突出的） brows.
[参考译文]根据人类学家的说法，直立行走的人的鼻祖面部轮廓与黑猩猩相似，额头后倾，眉毛突出。
5、Quails typically have short rounded wings that enable them to spring into full flight instantly（即刻地） when disturbed in their hiding places.
[参考译文]典型的鹌鹑都长有短而圆的翅膀，凭此他们可以在受惊时一跃而起，飞离它们的躲藏地。
6、No social crusade（改革运动） aroused（唤醒） Elizabeth Williams' enthusiasm more than the expansion（扩充） of educational facilities for immigrants to the United States.
[参考译文]给美国的新移民增加教育设施比任何社会运动都更多的激发了Elizabeth Williams的热情。
7、It is the interaction between people, rather than the events that occur in their lives, that is the main focus of social psychology.
[参考译文]社会心理学的主要焦点是人与人之间的交往，而不是他们各自生活中的事件。
8、The wallflower is so called because its weak stems often grow on walls and along stony cliffs for support.
[参考译文]墙花之所以叫墙花，是因为其脆弱的枝干经常要靠墙壁或顺石崖生长，以便有所依附。
9、The annual worth of Utah's manufacturing is greater than that of its mining and farming combined（组合的）.
[参考译文]犹他州制造业的年产值大于其矿业和农业的总和。
10、Because its leaves remain green long after being picked, rosemary became associated with the idea of remembrance（想念）.
[参考译文]采摘下的迷迭香树叶常绿不衰，因此人们把迷迭香树与怀念联系在一起。
11、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.
[参考译文]Alexander Graham Bell曾告诉家人，他更愿意让后人记住他是聋子的老师，而非电话的发者。
12、Elizabeth Blackwell, the first woman medical doctor in the United States , founded the New York Infirmary（治疗所）, an institution that has always had a completely female medical staff.
[参考译文]美国第一个女医生Elizabeth Blackwell，创建了一所纽约诊所，其全体员工一直以来都是女性。
13、By the middle of the twentieth century, painters and sculptors in the United States had begun to exert a great worldwide influence over art.
[参考译文]到了二十一世纪中叶，美国画家和雕塑家开始在世界范围内对艺术产生重大影响。
14、The mechanism（原理） by which brain cells store memories is not clearly understood.
[参考译文]大脑细胞储存记忆的机理并不为人明白。