单词:
单词: 相关文章
Conditions on Mars were so harsh that it was hard to imagine any life surviving there. The idea of sophisticated aliens was wiped out. We know that conditions on Mars today are not very good for life.
This is Scientific Americans -60 seconds science .I'm Steve Murskey.Got the minute? People with high blood pressure are often told to watch the salt, and it's long been far that hypertension related to excess salt is caused by the salt increasing in
金属切削 metal cutting 机床 machine tool 金属工艺学 technology of metals 刀具 cutter 电路 circuit 半导体元件 semiconductor element 反馈 feedback 发生器 generator 直流电源
A workboat pulls boom into place alongside the Pacific Responder oil skimming vessel in the Gulf of Mexico near the coast of Louisiana, 14 Jul 2010 BP has restarted a pressure test on a leaking oil well in the Gulf of Mexico to prepare for an effort
SCIENCE REPORT-January 10, 2002: New Glaucoma Treatments By Nancy Steinbach This is the VOA Special English Science Report. Sixty-seven-million people around the world cannot see because they suffer f