11. Acids are chemical compounds that, in water solution, have a sharp taste, a corrosive action on metals, and the ability to turn certain blue vegetable dyes red.
11. 酸是一种化合物，它在溶于水时具有强烈的气味和对金属的腐蚀性，并且能够使某些蓝色植物染料变红。12. Billie Holiday’s reputation as a great jazz-blues singer rests on her ability to give emotional depth to her songs.
12. Billie Holiday’s作为一个爵士布鲁斯乐杰出歌手的名声建立在能够赋予歌曲感情深度的能力。
13. Essentially, a theory is an abstract, symbolic representation of what is conceived to be reality.
14. Long before children are able to speak or understand a language, they communicate through facial expressions and by making noises.
15. Thanks to modern irrigation, crops now grow abundantly in areas where once nothing but cacti and sagebrush could live.
16. The development of mechanical timepieces spurred the search for more accurate sundials with which to regulate them.
17. Anthropology is a science in that anthropologists use a rigorous set of methods and techniques to document observations that can be checked by others.
18. Fungi are important in the process of decay, which returns ingredients to the soil, enhances soil fertility, and decomposes animal debris.
19. When it is struck, a tuning fork produces an almost pure tone, retaining its pitch over a long period of time.
20. Although pecans are most plentiful in the southeastern part of the United States, they are found as far north as Ohio and Illinois.