The third phase, to test whether the vaccine prevents real infection, has not yet been carried out, as there has been no massive spread of H5N1 influenza in people.

第三阶段临床试验用于测试该疫苗是否能够预防真正的传染，由于现在人群中还没有出现大规模的H5N1禽流感传染，所以该阶段还没有实施。

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The treatment caused her to lose her hair but, mercifully, the cancer had not spread and a recent test revealed she is now clear of the disease.

那些治疗让她失去了头发，幸运的是癌细胞不再扩散，而且不久前的检查她已没有癌细胞。

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That test spread debris in an area around the Earth filled with other satellites, endangering those machines.

这次试验产生的碎片散布在绕地轨道的某个布满卫星的区域中，给那些卫星带来的危险。

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Kennedy now contended that both sides had a vital interest in stopping the spread of nuclear weapons and slowing the arms race--a contention which led to the test ban treaty of 1963.

WHITEHOUSE: John F. Kennedy