单词：
单词： 相关文章
Cells cannot remain alive outside certain limits of temperature and much narrower limits mark the boundaries of effective functioning. Enzyme systems of mammals and birds are most efficient only withi
新东方背诵文选
Cold front to drop temperatures in north China BEIJING, Oct. 20 (Xinhua) -- China's meteorological authorities on Saturday forecast strong winds and temperature drops in most regions in the north due to a sweeping cold front. On Saturday and Sunday,
英语新闻
Some bacteria have adapted to super cold environments for millions of years. And scientists have isolated some of the essential genes that allow bacteria to tolerate their harsh living conditionsbecause these same genes might help in the creation of
英语杂谈
Every school day, about 7,000 students drop out of school(退学) in the United Stars. That's a total of 1.2 million students each year and only about 70 percent of entering high school freshman graduate each year. The problem is especially serious i
英语新闻