自1971年以来，这个机构的“专题”计划已甄选出了900多种可能致癌的因素，并把它们归为五类。

Since 1971 the agency's "monographs" program has evaluated more than 900 such factors, assigning each of them to one of five classification groups.

youdao

这周，读写网将发表一个系列专题，分析2009年的五大网络趋势。

This week ReadWriteWeb is running a series of posts analyzing the 5 biggest Web trends of 2009.

youdao

这周读写网将推出一个系列专题来分析2009年里五个最重要也是最前沿的网络趋势。

This week ReadWriteWeb is running a series of posts analyzing the 5 biggest, most cutting edge Web trends to come out of 2009.

youdao