必不可少

The experiments show that aeration and the alkaline environment are needed.

试验证明，曝气和碱性环境是必不可少的两个条件。

This aerator, with high efficiency and fast speed in increasing oxygen, is able to efficiently

该增氧机具有增氧速度快，增氧效率高，能有效地快速解决鱼池缺氧而引起的鱼类浮头和死亡现象，是科学养鱼，提高养殖密度，提高鱼池单位面积产量，提高养殖经济效益而必不可少的养殖机械。

The antenna is a necessarily important component in Radar system,whose stealth is a problem that puzzled the technology researchers all the while.The flight vehicle needs antenna to find its aim when reentering the aerosphere,and it also needs the protection by radome at the same time.

天线是雷达系统中必不可少的重要组成部分，其隐身是一个长期困扰着工程技术人员的问题，飞行器再入大气层时需要靠雷达天线来搜寻目标，雷达天线则需要天线罩来保护。

Including extending standards for green building, establishing owner inspiriting system and building affiance system, and developing popularity effect of green construction.

作为绿色建筑必不可少的组成部分，绿色施工被纳入绿色建筑评价体系是发展趋势。

For many people, aftercare such as taking medication or visiting an outpatient clinic is essential after a stay in hospital.

对于很多人来说，善后，如以药物或来访一门诊是必不可少后，留在医院接受治疗。

At the same time consistent air temperature and relative humidity of business card printing and membership card-making workshop climate and environment are essential.

同时，具有稳定的空气温度和相对湿度的制卡和会员卡制作车间气候环境也是必不可少的。

Air as well as sunlight, needless to say , is indispensable to our daily life.

空气正如阳光一样，不必说，它是我们日常生活中必不可少的。

A strong army and a strong airforce are indispensable to the defence of a land locked country.

一个强有力的陆军和一个强有力的空军对于保卫一个四周皆陆地的国家来说是必不可少的。

If you want your Alaskan Malamute to be a pleasure to own, it must have at least some basic obedience training.

如果你希望能快乐的拥有你的阿拉斯加，那一些基础的服从性训练是必不可少的 4。

For fundamental contributions to programming language design and the definition of Algol 60, to compiler design, and to the art and practice of computer programming.

诺尔为定义Algol 60程序设计语言做了很多先驱性工作，Algol 60是许多后来的程序设计语言，包括今天那些必不可少的软件工程工具的原型。

I didn't watch TV last night, because it .

昨晚我没有看电视，因为电视机坏了。

Since this year, in a lot of villages of Beijing, TV of elevator liquid crystal was removed.

今年以来，在北京的很多小区里，电梯液晶电视被撤了下来。