Molecular clouds play an integral role in the prestellar evolutionary sequence of interstellar matter . 分子云在星际物质的星前期演化序列中起着不可缺少的作用。
In this age of international travel, language ability is also a definite aid in hotel work . 在当今国际旅游盛行的时代，语言能力也是搞好旅馆工作的一个不可缺少的条件。
These executives, expert in every phase of corporation, became the indispensable cogs in the industrial machine . 这些高层管理人员精通公司的各项业务，成为整个工业机器中不可缺少的齿轮。
Difunctionality, which is the essential characteristic of a polymer precursor, may be achieved in many different ways . 能生成聚合物的物质其不可缺少的特点是具有双官能性。这种双官能性可用多种方法获得。
These senior executives, expert in every phase of corporate activity, become the indispensable cogs in the industrial machine . 这些高层管理人员精通公司的各项业务，因而成为整个工业机器中不可缺少的轮齿。
It is essential of activities out of class 课外活动是学校生活不可缺少的一环。
That you are indispensabie to his organization .你对他的公司来说是不可缺少的
E - mails are now a part and parcel of life 电子邮件已成为生活中不可缺少的一部分。
The arms and legs are integral parts of a human body 臂和腿是人体不可缺少的部分。
