不可缺少

The thatched roof is an essential part of the attraction of the English countryside.

essential（意思是必要的，不可缺少的，）对应问题中的unique属于同义替换。

To be without some of the thins you want is an indispensable part of happiness.

有些东西你想要而没有，这是幸福不可缺少的一部分。

The study of Drug Toxicology plays an important role in guiding the research and development of new drugs and in the risk assessment of drugs' toxicities.

药物毒理学研究是指导新药研究与开发，对药物的毒性进行危险性评估不可缺少的重要手段。

As transport is an integral part of import and export trade, Guangzhou Sea Coast has integrated freight agency services of international ocean freight and airfreight, including the one-stop all-round high quality service of shipping pace booking, warehousing and storage, supervision of loading,LCL,sea transport, air transport, customers declaration,trailering,and insurance.

广州安汝之国际货运代理有限公司是一家专业的国际货物运输企业，运输作为进出口贸易不可缺少的一部分，我司将运输代理服务融入进出口代理服务当中，主要向客户提供海运、空运的国际运输代理业务。

The construction of knowledge is an essential part in foreign language learning since it widens our cognitive context.

外语学习中外语知识的建构对扩大认知语境有益，是外语学习不可缺少的部分。

For about 50 years, until the end of last century, teachers and students of English in China regarded Queen's English as the sole standard, and the IPA was a compulsory course in schools and an independent item for the annual national university entrance English examinations.

直到上世纪末，大约五十年以来，中国的英语老师和学生都把以国际音标为依据的英语普通话视为英语的唯一标准。国际音标是学校的必修课，也曾是高考英语试卷中不可缺少的内容。

For about 50 years, until the end of last century, teachers and students of English in China had been regarding the Queen's English as the sole standard, and the IPA had been a compulsory course in schools and an independent item for the annual national university entrance English examinations.

直到上世纪末，大约五十年以来，中国的英语老师和学生都把以国际音标为依据的英语普通话视为英语的唯一标准。国际音标是学校的必修课，也曾是高考英语试卷中不可缺少的内容。

For about 50 years, until the end of last century, teachers and students of English in China had been regarding the Queen's English as the sole standard, and the IPA had been a compulsory course in schools and an independent item for the annual national university entrance English examinations.

直到上世纪末，大约五十年以来，中国的英语老师和学生都把以国际音标为根据的英语普通话视为英语的唯一标准国际音标是学校的必修课，也曾是高考英语试卷中不可缺少的内容在上世纪七十年代，中国引进了《灵格风英语教程》，八十年代引入了《跟我学》电视英语以及至今仍十分风行的《新概念英语》通过这些标准优雅的英语普通话的学习，至少有两代中国学习者掌握了基础的英语发音

As you can see, the outdoor sink is an indispensable part of outdoor kitchens.

您能看到，室外水槽是室外厨房的一个不可缺少的部分。

There is no food that is essential, but there are nutrients that are necessary for good health.

没有哪种食物是必不可少的，但有些营养成分对身体健康是不可缺少的。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。