必不可少

In contrast,the imides derivatives of maleated polyethylene are stable for long periods of time at 160℃,and the decomposition of phenethylamine imide-,9-aminomethylphenanthrene imide-derivatives is initiated slowly at 255℃ and 280℃,respectively.

聚乙烯的化学改性已得到广泛应用，它能使PE获得新的物理化学或功能特性，如改进其表面粘合、亲水及吸湿、染色和印刷性质等，尤其在增加它与其它聚合物的相容性，制备共混材料时常常是必不可少的[1 ，2 ] 。

There are a reasonable number of elements that any self improver should consider through his or her self improvement efforts; each one of those elements is indeed an essential.

有一个合理的数目的元素，任何自我改良剂应考虑通过他或她的自我改善的努力，每一个这些因素的确是必不可少的。

In statistical language modeling, large amounts of text are used to automatically determine the model's parameters.

语言模型在语音识别、机器翻译和任何对自然语言知识进行应用的领域中都是必不可少的。

In order to purchase the residence after obtaining a satisfactory quality of life, a good property management is essential.

以购买的住宅后，获得了令人满意的生活质量，良好的物业管理是必不可少的。

"Silent", the film has never been, in the full sense of the word, silent.

尽管我们习惯于将 1927 年以前的电影称为"无声电影"，但是就无声这个词完整的意义上来说，电影从未真正的无声过，从最初开始音乐就被视为必不可少的伴奏。

Accustomed though we are to speaking of the films made before 1927 as "silent", the film has never been, in the full sense of the word, silent. From the very beginning, music was regarded as an indispensable accompaniment

尽管我们习惯于将1927年以前的电影称为"无声电影"，但是就无声这个词完整的意义上来说，电影从来真正的无声过，从最初开始音乐就被视为必不可少的伴奏。

It is very important for students to grasp a certain amount of words in the course of language-learning.

在任何语言的学习中，掌握一定的词汇是必不可少的。

At present, the communication facilities are developed, a friend of the regular contact by telephone, call become an indispensable element in daily life, while in her class of children aged too small and most are single children now, the prevailing there inadvertence The act, so this game full of characteristics of the times and with the current child care characteristics of the age.

目前，通讯设施非常发达，朋友间经常以电话联系，打电话成了人们日常生活中必不可少的内容；同时中班上册幼儿年龄偏小且现在多数都是独身子女，普遍存在出现粗心大意的行为，所以这一游戏既富有时代特征又符合当前幼儿的年龄特点。

Since fast algorithm for multiwavelet decomposition and reconstruction are crucial steps inapplication,discretion form of multiwavelet is obviously necessary.This dissertation makes asuccessful exploration in this aspect,synchronously designs a new pre-filter method for multiwavelet,and gives evaluation regulations of pre-filters for different objects.These research results providereliable guarantee for exploration and study of multiwavelet application.

由于向量小波的分解、重构快速算法在应用中是必不可少的重要环节，故必须给出向量小波的离散化形式，本文在这方面做了成功的探索，同时还设计了一种新的向量小波的预滤波器，并给出了选择适合于不同对象的预滤波评判准则，这些研究成果使向量小波应用潜力和应用前景的拓展有了可靠的保证。

This is essential for outstanding achievement because it involves your natural ability to comprehend difficult concepts quickly and to analyze them clearly and incisively.

这一点是取得杰出成就必不可少的，因为它包括迅速理解困难的概念并能明了、地分析它们的能力。

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。