下列说法中正确的是( ) A.分解反应不一定有单质生成 B.化合反应一定有单质参 发布时间:2017-06-24 22:46 │ 来源:www.tikuol.com 题型:选择题 问题: 下列说法中正确的是( )A.分解反应不一定有单质生成B.化合反应一定有单质参加C.原子变成离子时一定得到电子D.只有最外层为8个电子的结构才为相对稳定结构
题型:选择题 Directions: There are 10 blanks in the following passage. For each numbered blank, there are 4 choices marked A, B, C and D. It is difficult to imagine what life would be like without memory. The meanings of thousands of everyday perceptions, the bases (51) the decisions we make, and the roots of our habits and skills are to be (52) in our past experiences, which are brought into the present (53) memory. Memory can be defined as the capacity to keep (54) available for later use. It includes not only "remembering" things like arithmetic or historical facts, but also any change in the way an animal typically behaves. Memory is (55) when a rat gives up eating grain because he has sniffed something suspicious in the grain pile. Memory is also involved when a six-year-old child learns to swing a baseball bat. Memory (56) not only in humans and animals but also in some physical objects and machines. Computers, for example, contain devices for storing data for later use. It is interesting to compare the memory-storage capacity of a computer (57) that of a human being. The in stant-access memory of a large computer may hold up to 100 000 "words" —ready for (58) use. An average American teenager probably recognizes the meanings of about 100 000 words of English. However, this is but a fraction of the total (59) of information which the teenager has stored. Consider, for example, the number of facts and places that the teenager can recognize on sight. The use of words is the basis of the advanced problem-solving intelligence of human beings. A large part of a person’s memory is in terms of words and (60) of words.A.toB.withC.againstD.for 查看答案
题型:选择题 某患者以乏力、肥胖,高血压就诊,化验检查空腹血糖为7.2mmol/L。如为老年患者,伴剧烈呛咳则应考虑()A.嗜铬细胞瘤B.肺癌、异位内分泌综合征C.糖尿病,肺癌D.糖尿病伴肺部感染E.高血压病、糖尿病 查看答案
题型:选择题 受西方的影响,中国近代传统的礼仪和婚姻都发生了重大变化。下列关于近代婚姻风俗的变革,符合史实的有( )①主要发生在通商口岸,婚姻变革主要发生在知识层和官宦人家②民国初年,旧有的婚姻观念没有完全改变③新文化运动和国民革命洪流,推动了近代婚姻的变革进程 ④广大的农村和内地没有多大变化A.①②③B.②③④C.①④D.①②③④ 查看答案