不是必要的

The second order asymptotic formulation for reliability analysis of parallel systems is employed in calculating the fatigue failure probability of the failure path of the system.

由于结构系统的疲劳破坏是一个受到大量不确定因素影响的现象，因此运用结构可靠性分析的基本理论和方法，对结构系统进行疲劳可靠性分析十分必要。

It is very unwise to take legal action against someone unless it is absolutely necessary.

如果没有绝对的必要就对某人起诉是很不明智的。

Thus, there is a duplication of effort that lengthens the process and increases costs unnecessarily.

因此，这是一种延长诉讼过程和增加不必要费用的无用的努力。

Reefs, reef-mounds and lime mud mounds are all carbonate buildups, and the reefs and banks are important targets for petroleum exploration The reefs, banks and mounds should be divided from each other not only in theory, but also in exploration practice, because of so many differences in sedimentary compositions, fabrics, environments, distribution in time and space, and the characteristics of petroleum geology If the original reef or bank itself was fine reservoir rocks, then it would become a better reservoir after the reservoirconstructive diagenesis The formation of a high quality carbonate reservoir is controlled by two factors: the sedimentary microfacies and the reservoirconstructive diagenesis The first is the basis for the formation of a high quality reservoir, and with the high energy reefbank facies as the best; the latter includes the cataclasis, the dolomitization and the karstification The dolomitization and karstification are the best for the formation of a high quality reservoir The karstification has the widest distribution, profoundest effect, and plays a vital role in the high quality reservoir forming The karst types are quite rich in the limestone reef or bank reservoir, including synsedimentary karst, penesedimentary karst, supergene karst and hydrothermal karst, and so does the dolomitization reef or bank reservoir The formation mechanism of synsedimentary karst and penesedimentary karst is related to the short time exposing and leaching of the cyclical highfrequency shallowupward sequence when the reefs or banks are forming The supergene karst is controlled by the exposing and leaching of tertiary cyclic sequence type I interface after the reefs or banks forming Thus, there developed a great deal of secondary corrosion pores, corrosion fractures and huge caves besides some original pores remained in the reef and bank reservoir Scarcely there are any original effective pores in reefmounds and lime mud mounds, especially in senkes among mounds, but secondary pores could be formed by karstification, and there would likely develop source rocks with high organic abundance

礁、礁丘、丘同属碳酸盐建隆，礁、滩是重要勘探目的层。但各自在沉积组分、组构、环境和时空分布，以及油气地质条件上迥然不同，因而无论从理论还是勘探实践上，都有必要将其各成体系划分开来。礁滩自身为好储集岩，当建设性成岩作用叠加后可形成好的储层。碳酸盐岩优质储层形成，主要受沉积微相与建设性成岩作用两大因素控制。前者是基础，并以高能的礁滩相带为最好；后者主要包括破裂、白云石化和溶蚀三大类，并以白云石化或溶蚀为最优，其中的溶蚀分布最广泛、影响最深刻而对优质储层形成起决定性作用。礁滩储层中的古岩溶类型最为丰富多彩，包括同生期、准同生期、表生期和埋藏期热流体岩溶的所有类型，白云岩化礁滩体也不例外。其中，同生准同生期岩溶的形成机制与礁滩沉积时高频层序旋回向上变浅序列的短暂暴露淋溶有关，表生期岩溶则受控于礁滩沉积后三级层序旋回Ⅰ型界面的暴露淋溶。由此，导致礁滩储层中除了可以也是唯一保存原生孔隙外，还发育了次生溶蚀孔洞缝和大型溶洞。礁丘、灰泥丘尤其是丘间洼地中发育高有机质丰度烃源岩；它们自身没有有效的原生孔隙，但岩溶作用可以形成次生孔隙。

But, at present, the construction of forage grass material base, the road traffic, and the trading market can not satisfy the realistic need in this area, all these should be improved under the government's help.

但不足的是，目前饲草料基地建设、道路交通和交易市场还不能满足实际需要，有必要在政府的帮助下切实地加以完善。

The frustrations of not knowing exactly what's 'round about you doesn't necessarily show in this film," he said."All of our characters are space traveling, and the fact that there are thousands of speeders going past us outside the window is an everyday occurrence.

不知道自己周围究竟发生了什么事的挫败感没有必要表现在这部电影里，&他说，&我们所有的角色都是太空飞行员，窗外有成千上万的飞行器从我们身边飞过的景色其实是每天都发生的事。

But capital is profit-seeking, so do multinational companies. And transfer price is an important tool to gain high profit of them, so there is necessity to study about it.

但是资本本身是逐利的，跨国公司也不例外，它们进入每一个领域和市场的目的都是获取利润，而内部转移价格正是跨国公司实现其目的的重要手段，因此，有必要对跨国公司的内部价格进行深入的研究。

The ideas of simplification and generalisation had always been associated with the conception of Nature; simplicity, symmetry, and intelligibility came therefore to be regarded as the characteristics of a good legal system, and the taste for involved language, multiplied ceremonials, and useless difficulties disappeared altogether.

单纯化和概括化的观念，是常常和&自然&这个概念联系着的；因此单纯匀称和通晓易懂就被认为是一个好的法律制度的特点，过去对于复杂言语、繁褥仪式和不必要困难的好尚，便完全消除。

Renfrew and Bahn instead are able to make understandable different theories, very important to comprehend what archaeology should look for; also the series of methods presented are virtually complete and updated, with the necessary space given to the new scientific approaches and analysis of material evidence; but the practice is far from the reality.

伦福儒和巴恩却是能够创造出为人理解的各种理论，这对于了解考古学家在找寻什么非常重要；而对给予新的科学方法和物质证据分析的必要空间后，这一系列的方法事实上也很完善、现代化；可惜的是实践起来不太现实。

Troy Nkrumah, the chairman of the National Hip-Hop Political Convention, thinks it wonderful that Lil Wayne is speaking truth to power.

不过，假如要严肃认真对待小韦恩，那很有必要指出他所谓&九分之一&的数字是不准确的———惟有界定在20

However, as the name（read－only memory）implies, CD disks cannot be written onorchanged in any way.

然而，正如其名字所指出的那样，CD盘不能写，也不能用任何方式改变其内容。

Galvanizes steel pallet is mainly export which suits standard packing of European Union, the North America. galvanizes steel pallet is suitable to heavy rack. Pallet surface can design plate type, corrugated and the gap form, satisfies the different requirements.

镀锌钢托盘多用于出口，替代木托盘，免薰蒸，符合欧盟、北美各国对出口货物包装材料的法令要求；喷涂钢托盘适用于重载上货架之用，托盘表面根据需要制作成平板状、波纹状及间隔形式，满足不同的使用要求。