这项最新研究还包括一个历时半年的干预计划，以帮助母亲们减少其宝宝接触二手烟烟雾的伤害。
The new research also included a six-month intervention program to help mothers decrease their child's exposure to secondhand tobacco smoke.
此次调查历时半年多，以全国10岁至18岁的在校学生为主，在全国106所中小学校开展。
The survey, which was conducted over 6 months, included mainly students between 10 and 18 in 106 middle and elementary schools across the country.
另一方面，我国股票市场自2005年下半年以来走出了一轮历时虽不长，然涨幅较罕见的牛市行情。
On the other hand, Chinese stock market has stepped in a magnificent bull market since June 2005, the rising speed of stock is unprecedented in history.
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