Over the year, her son's eighth grade class saved up money and worked on projects so that next week they could take a class trip to Washington, D. c.

过去一年，她儿子所在的八年级存下了一些钱，并制定了一个计划，下周，他们将参加班级旅行来到华盛顿特区。

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The new killer bug C. difficile has flourished because older antibiotics killed off the healthy bacteria that normally live in the intestine, clearing the way for toxic C. difficile to take over.

FORBES: Germ Warfare

The new bugs multiply rapidly and take over the lower intestine, driving C. difficile away.

ECONOMIST: The human microbiome