幕状星云

available, [ ə'veiləbəl ] adj 可用的,可得到的 【例】He is not available for the job 他不适宜做这个工作。This book is not available here 这里没有这本书。 【根】avail效用。参:availability(n 可用性,实用性

发表于:2018-12-30 / 阅读(46) / 评论(0) 分类 不择手段背单词

This is Scientific Americans 60-Second Science. Im Karen Hopkin. This will just take a minute. If youve ever wondered where the Earth came from, the answer, it seems, is blowin in the windthe solar wind. Or so say scientists who, after examining sola

发表于:2019-01-08 / 阅读(61) / 评论(0) 分类 Scientific American(七)月

反射星云是靠反射附近恒星的光线而发光的,呈蓝色。反射星云的光度较暗弱,较容易观测到的例子是围绕着金牛座M45七姊妹星团的反射星云,在透明度高及无月的晚上,利用望远镜便可看到

发表于:2019-01-08 / 阅读(175) / 评论(0) 分类 托福英语

The Aeneid by Virgil 《埃涅阿斯纪》维吉尔 Mark first read the Aeneid while he was studying Latin in high school, and he recountedthe story of Aeneass quest and his desire to build a city that, he said, quoting the text in English, knows no

发表于:2019-01-17 / 阅读(40) / 评论(0) 分类 阅读空间

The Aeneid by Virgil 《埃涅阿斯纪》维吉尔 Mark first read the Aeneid while he was studying Latin in high school, and he recounted the story of Aeneass quest and his desire to build a city that, he said, quoting the text in English, knows no

发表于:2019-02-01 / 阅读(29) / 评论(0) 分类 阅读空间

It looks like a hand of God reaching out into the cosmos, but NASA says the display is caused by a young and powerful pulsar. Taken by NASA's Chandra X-ray observatory from it's orbiting 360 miles above the Earth, the recently released photo of Pulsa

发表于:2019-02-16 / 阅读(74) / 评论(0) 分类 实用英语