36套，ex21两问

zhj0735UID: 2561218

将超新星和星云的长文章，不贴了。
5.According to information provided by the passage,which of the following stars would astronomers most likely describe as a  lanetary nebula?
(A) A star that began its life with a mass of 5.5 M⊙, has exhausted its nuclear fuel, and has a core that is visible to astronomers
(B) A star that began its life with a mass of 6 M⊙, lost mass at a rate of 1 M⊙ per 10,000 years, and exhausted its nuclear fuel in 40,000 years
(C) A star that has exhausted its nuclear fuel, has a mass of 1.2 M⊙, and is surrounded by a circumstellar cloud that obscures its core from view
(D) A star that began its life with a mass greater than 6 M⊙, has just recently exhausted its nuclear fuel, and is in the process of releasing massive amounts of gravitational energy
(E) A star that began its life with a mass of 5.5 M⊙, has yet to exhaust its nuclear fuel, and exhibits a rate of mass loss similar to
that of IRC+10216
我选D，答案A。请告诉我为啥D错A对？  木有提到5.5呀~



One of the questions of interest in the study of the evolution of spiders is whether the weaving of orb webs evolved only once or several times. About half the 35,000 known kinds of spiders make webs; a third of the web weavers make orb webs. Since most orb weavers belong either to the Araneidae or the Uloboridae families, the origin of the orb web can be determined only by ascertaining whether the families are related.
Recent taxonomic analysis of individuals from both families indicates that the families evolved from different ancestors, thereby contradicting Wiehle‘s theory. This theory postulates that the families must be related, based on the assumption that complex behavior, such as web building, could evolve only once. According to Kullman, web structure is the only characteristic that suggests a relationship between families. The families differ in appearance, structure of body hair, and arrangement of eyes. Only Uloborids lack venom glands. Further identification and study of characteristic features will undoubtedly answer the question of the evolution of the orb web. (172 words)

8. The primary purpose of the passage is to？
(A) settle the question of whether orb webs evolved once or more than once
(B) describe scientific speculation concerning an issue related to the evolution of orb webs
(C) analyze the differences between the characteristic features of spiders in the Araneidae and Uloboridae families
(D) question the methods used by earlier investigators of the habits of spiders
(E) demonstrate that Araneidae spiders are not related to Uloboridae spiders
答案B，我选C。
文章显然大篇幅讲不同点啊，织网的特征只是表征不同的其中一种表现方式，并非主要话题~~请求指教~

另外，请问是否有当前Issue 题库的高频统计神马的呢？谢谢谢谢！

zhj0735UID: 2561218

MIA~~求高手相助！