Volcanic rock can become favorable oil-gas reservoirs.

It's built on volcanic rock and ash.

该城建立在火成岩与火山灰上.

I had to do an in-class presentation on volcanic rock formation.

我曾在班内做过一次关于火山岩成因的讲演.

Prostaglandin ( PG) D_2 is one of unsaturated fatty acids with 20 carbon atoms, which is synthesized by PGD synthase ( PGDS) in the brain.

前列腺素D2（PGD2）是由前列腺素D2合成酶合成的一种二十碳不饱和脂肪酸。

Objective: Porphyromonas gingivalis ( Pg) is one of the main putative pathogens of periodontal disease, especially of adult periodontitis.

目的：探讨牙周炎主要病原菌牙龈卟啉单胞菌（Pg）对常用抗菌药物的敏感性。

[ Objective] Streptococcus sanguis ( Ss) is one of the most popular bacteria in the oral cavity, which associates with various diseases. Porphyromonas gingivalis ( Pg) is one kind of anaerobic gram-negative bacteria associated with the chronic periodontitis.

[目的]血链球菌（Ss）是一种与许多疾病相关的口腔中最常见的细菌，牙龈卟啉单胞菌（Pg）是一种与慢性牙周疾病相关的革兰氏阴性的厌氧菌。

The politics of the Security Council are even more outdated.

安理会的政治更是过时.

The problem of the Security Council is how to become more effective.

五大常任理事国应考虑各成员国的外交需求和民族利益、事先取得一致,以此提高效率.

The uk used its veto in the security council.

英国在安理会行使了否决权.

He gave a flat assurance that they would introduce no resolution in the Security Council.

他直截了当地保证他们不会在安理会提出任何决议案.

How did it happen that the proposal was vetoed at the Security Council?

这项提案在安理会遭到否决是怎么搞的?

A Security Council meeting was likely to generate rhetoric that put us on the defensive.

安理会如果开会,很可能会引出使我们处于守势的讲话.

The organ which has the primary responsibility for maintaining peace and security is the Security Council.

负有维护和平与安全的主要责任的机构是安全理事会.

The Security Council has rejected the latest peace proposal.

安理会拒绝了最新的和平提案。

The two groups of walkers joined up for the rest of the holiday.

两组步行度假者会合一起度过剩下的假期.

The small boy soon became tired and lagged far behind ( the rest of the walkers ).

那小男孩儿不久就走不动了,远远落在 ( 其他人的 ) 后面.

The Walkers have 20 pounds coming in weekly.

沃克一家每星期有二十镑收入.

If you do not cross at the crosswalk, you are called " jade-walkers. "

如果你不是由人行横道穿过马路, 就被称为 “ 不守交通规则的行人 ”.

Searchers looking for three lost climbers in Oregon will use a helicopter to help them.

寻找在俄勒冈州失踪的三个登山者的搜寻员们将会使用直升机来帮助他们.

Searchers rescued the boys lost in the mountains.

搜索者救出了在山中迷失的男孩子们.

Do Chinese searchers interact differently than North American searchers?

中国人的搜索行为与北美的那些中国人有差异 吗 ?