首页
登录
职称英语
Natural flavorings and fragrances are often costly and limited in supply. Fo
Natural flavorings and fragrances are often costly and limited in supply. Fo
游客
2025-01-28
12
管理
问题
Natural flavorings and fragrances are often costly and limited in supply. For example, the essential ingredient in a rose fragrance is extracted from natural rose oil at a cost of thousands of dollars a pound; an identical synthetic substance can be made for 1% of this cost. Since the early twentieth century, success in reproducing these substances has created a new industry that today produces hundreds of artificial flavors and fragrances.
Some natural fragrances are easily synthesized; these include vanillin, the aromatic ingredient in vanilla, and benzaldehyde, the aromatic ingredient in wild cherries. Other fragrances, however, have dozens, even hundreds of components. Only recently has it been possible to separate and identify these ingredients, by the use of gas chromatography and spectroscopy. Once the chemical identity is known, it is often possible to synthesize them. Nevertheless, some complex substances, such as the aroma of fresh coffee, have still not been
duplicated
satisfactorily.
Many of the chemical compounds making up these synthetics are identical to those found in nature, and are as harmless or harmful as the natural substances. New products must be tested for safety, and when used in food, must be approved by the U.S. Food and Drug Administration.
The
availability
of synthetic flavors and fragrances has made possible a large variety of products, from inexpensive beverages to perfumed soap to used cars with applied "new car odor". [br]
The delegates coming this far, they
did not want to return without accomplishing something.
选项
A、The delegates came this far, they
B、Coming this far, the delegates felt they
C、Having come this far, the delegates
D、To come this far, the delegates
答案
C
解析
转载请注明原文地址:http://tihaiku.com/zcyy/3932895.html
相关试题推荐
Thelimitedgaincouldhardlyserveasarelievingjustificationforthetremend
Norwayis,quitenaturally,payinggreatattentiontodevelopmentsinEuropeand
Naturalflavoringsandfragrancesareoftencostlyandlimitedinsupply.Fo
Naturalflavoringsandfragrancesareoftencostlyandlimitedinsupply.Fo
Thefirstrecordeduseofnaturalgastolightstreetlampsitwasinthetowno
Thefirstrecordeduseofnaturalgastolightstreetlampsitwasinthetowno
Naturalflavoringsandfragrancesareoftencostlyandlimitedinsupply.Fo
Naturalflavoringsandfragrancesareoftencostlyandlimitedinsupply.Fo
Naturalflavoringsandfragrancesareoftencostlyandlimitedinsupply.Fo
Naturalflavoringsandfragrancesareoftencostlyandlimitedinsupply.Fo
随机试题
[originaltext]WeddingintheUnitedStatesvaryasmuchasthepeopledo.T
PresidentCoolidge’sstatement,"ThebusinessofAmericaisbusiness,"still
下列选项中,关于法律责任的表述,哪些选项是错误的?()A.钱某在街道走路,被街
下列钢筋混凝土框架结构的抗震设计做法中,正确的是( )。A.宜采用单跨框架
投资顾问业务的客户回访应() Ⅰ.另设回访机制 Ⅱ.全面回访 Ⅲ.回访
巴金的“爱情三部曲”包括的作品是()。 A.《雾》B.《雨》C.《火》
在我国,为了贯彻分业经营的原则,商业银行不能从事以下哪些业务( )A.信托投资
报检人对检验检疫机构的检验结果有异议需复验的,可以向()申请。 A原检验检疫
开工前复核基准点、基准线和高程时发现问题,应从()获取准确结果。A.设计单
(2017年真题)根据分部组合计价原理,单位工程可依据()等的不同分解为分
最新回复
(
0
)