对...必需

In our pioneering days this aggressiveness was essential to survival. Now it can be a menace to society.

在拓荒时代，这种攻击性是生存所必需的，但现在可能是一种对社会的威胁。

An essential amino acid that is important for the growth and repair of tissue.

一种必需氨基酸，对组织的生长和修复有重要作用。

The kinetochore generates the force that is essential for the complex series of chromosome movements that lead to their aligment at metaphase and segregation at anaphase.

着丝点产生对一系列复杂的染色体运动所必需的力，导致染色体中期的调整和后期的分离。

It is shown that the exogenous hormones are not necessary to initiate the androgenesis,but they can promote further growth of pollen embryoids and calluses.

外源激素对于雄核发育的启动不是必需的，但对愈伤组织进一步的生长却是不可缺少的。

The results suggested that selenium might antagonize the neurotoxicity of fluoride on behavior and morphology.

硒是人体必需的微量元素，大量研究表明：适当浓度的硒对氟中毒有较强的拮抗作用[5～ 7] 。

Retinal laser photocoagulation is necessary for the peripheral lattice retinal degeneration associated with hole, vitreous traction, local detachment, aphakic eye or pseudoplatic eye to prevent retinal detachment, and it is effective and safe.

对伴有干性裂孔、玻璃体牵引、一眼已有视网膜脱离、无晶状体或人工晶状体眼的周边部视网膜格子样变性进行预防性激光光凝治疗是必需、安全和有效的。

To emphasize it gives the apologist several advantages:(1) Inquirers sometimes tell us that there is no point in investigating Christianity, for if they did that, they would also have to investigate all the other religions, philosophies, and ideologies in the history of thought – an impossible task, to be sure.

强调基督教位格性的世界观，能给护教者们带来几方面的好处﹕(1)有些慕道朋友对我们说﹕「探索基督教是毫无意义的，因为若要进行这样的探索，我们必需同时研究思想史上所有其他的哲学、宗教与意识型态，这当然是不可能的。

If you are not familiar with the apparel market, you need to be familiar with on again

如果你对服装市场不熟悉的话，你就必需先熟悉了再做

He has refused his assent to laws, the most wholesome and necessary for the public good.

他拒绝批准对公众利益最有益、最必需的法律。

Barley is the main stuff of beer brewing and chromium is a vital trace element to human. Potassium chromium sulfate was added to the water during the barley infusion and enriched-Cr malt was executed.

啤酒酿造的主要原料是大麦，铬是人体必需的一种微量元素，本文在浸麦过程中用KCr(SO_4)_2处理麦芽，制成了富铬麦芽，研究了铬对麦芽生理生化特性及成品麦芽质量的影响。

Since historical times,England ,where the early inhabitants were Celts, has been conquered three times .

从有历史以来，英国，在此地早期居住的是凯尔特人，已经被征服了三次。

Bluetooth OBEX File Transfer Enables the sending and receiving of files on your phone via Bluetooth.

蓝牙OBEX文件移动允许经过蓝牙传送和接受文件。。。。