为正常播放该音频，请使用IE9及以上版本IE浏览器或其它浏览器。 Scientists from the Hefei Institutes of Physical Science (HIPS) under the Chinese Academy of Sciences have designed a wristwatch that can measure essential chemicals ...

The central parity rate of the yuan against the U.S. dollar is based on a weighted average of prices offered by market makers before the opening of the interbank market each business day. The central ...