The subject of rock 'n' roll has been controversial and a source of conflict between parents and children ever since it first appeared on the scene in the mid 1950's.

自从二十世纪五十年代中期诞生以来，摇滚乐就一直是父母和孩子之间冲突的原因之一。

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The study of geochemistry indicates that these metabasic volcanic rocks are characterized with N-type MORB (mid-ocean ridge basalt).

地球化学研究表明，其为典型的大洋拉斑玄武岩（MORB型玄武岩）。

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"North Korea changed their behavior and words from mid-July, that's the point U.N.Security Council resolution 1874,to be implemented,".

VOA: standard.2009.12.08

Some recent studies have revealed a significant concentration of particles in near-surface waters in areas of mid-ocean accumulation (N Pacific and NW Atlantic gyres).

UNESCO: All Events | United Nations Educational, Scientific and Cultural Organization

The U.N. has an office of internal oversight, set up at U.S. behest as part of a push for U.N. reform in the mid-1990s.

FORBES: Keep An Eye On The U.N.

And Prime Minister Hun Sen, who has been in power since the mid-1980s, has portrayed the U.N. recognition as a national triumph.

CNN: Cambodia reports Thai incursions to U.N.