At least 90 percent of UFO sightings can be identified as conventional objects, although time-consuming investigations are often necessary for such identification. The objects most often mistaken for UFOs are bright planets and stars aircraft, birds, balloons kites aerial flares, peculiar clouds, meteors and satellites. The remaining sightings most likely can be attributed to other mistaken sightings or to inaccurate reporting hoaxes or delusions although to disprove all claims made about UFOs is impossible

violent crimes robbery, aggravated assault hijack forcible rape, murder, bombing kidnapping, shooting a Property crimes arson, burglary, larceny-theft, fraud, motor/ vehicle theft Neighborhood Watch in Britain, there is an arrangement by which people who live in a particular

1. grasp the main idea( tolerance for solitude and energy made it possible for the writer s family to enjoy their pleasant but sometimes harsh country life.) 2. appreciate the various techniques employed by the writer comparison and contrast, topic sentences followed by detail sentences

Teaching Objectives 1)understand the main idea(despite the many negative effects of virtual life the author prefers it to real life) and the structure of the text(contrast between virtual life and real life); -2)learn some rules of interpreting new vocabulary

1. understand the main idea (despite his wealth, Sam Walton remains down-home and devoted to his team) and the structure of the text; 2. appreciate the use of indirect description in portraying person: 3. grasp the key language points and grammatical structures in the text

§1 机械波的产生和传播 §2 一维简谐波的表达式 §3 波动方程和波速 §4 波的能量 §5 惠更斯原理 §6 多普勒效应 §7 波的叠加 §8 驻波(standing wave) §9 波的干涉

第四章参考答案: 1.全相联直接相联组相联段相联 2.体内连续编址体间连续编址同步启动异步启动 3.虚拟存储器命中率H存储空间利用率u

§1-1 测量学的内容与任务 §1-2 测量学的发展与作用 §1-3 地球的形状和大小 §1-4 地面点位的确定 §1-5测量工作的基本概念 ◼基本原则 ◼控制测量 ◼地形测量 ◼施工放样 ◼基本观测量 距离 角度 高差 §1-6地球表面曲率对测量工作的影响 § 1-7 测量的度量单位

第六章多机系统 1概述 一、并行性概念 并行性是指在执行任务过程中可同时进行的运算或操作。 1.开发并行性的目的提高计算机的运行效率 2.并行性的含义 具有双重含义:同时性与并发性同时性是指两个或两个以上的事件在同一时刻发生。并发性是指两个或两个以上的事件在同一时间间隔内发生

第二章数据表示与指令系统 1数据表示 一、数据表示的确定 1.何谓数据表示 由硬件直接识别和处理(引用)的数据类型, 2.数据表示的主要类型 （1)常用数据表示:定点数、字符串、浮点数等。 （2)高级数据表示:自定义、向量、堆栈数据表示 3.数据表示与系统结构的关系 （1)数据表示是硬件设计基础 （2)数据表示是指令加工的对象