Atomic Structure All natural and most synthetic substances on earth are made from the ninety naturally occurring chemical elements. An atom is the smallest particle into which an element can be divided while still retaining the chemical characteristics of that element (fig 3. 1). The nucleus, at the center of the atom contains one or more particles with a positive electrical charge(protons fif and usually some particles of similar mass that have no charge(neutrons

ChapterⅣ Syntax Syntax and grammar Syntax: A Definition Syntax and chomsky

Directions: Choose the best answer to complete each of the following sentences 1.The assignment for Thursday is to write composition about your hometown A)a five-hundred-words B)a five-hundred-word C)a five-hundreds-word D)a five-hundreds-words

Part i Vocabulary Structure(25%) Directions: There are 25 incomplete sentences here, each with a blank. You are required to complete each one by choosing the most appropriate answer from the 4 choices marked A.B.c and D 1. Molly watching football matche T B. interested C. ke

宇物是由哪些基本物质构成的呢?人类 从:上古代起就开始了关于物质结构的探讨 到世纪视瑟福根据a粒子衍射现象提出 了“含核的原模型”。 1913年波分提了核外电子分层排布的波 尔理论 直到20世纪30年代,以微观粒子波粒象 性为基展来的量子力学,比 观界实际的物质结构近代理论

Exercises( Units One- Five) I Vocabulary and structure 1. On my way to school, I saw people advertisements and sample products A conveying B creating C discarding D distributing

Pili and fimbriae G short, fine, hairlike appendages that are not involved in motility Fimbriae/fimbria: 1000piece/cell, adhesion to host epithelium Sex pill/pilus: 1-10piece/celly sexual conjugation, they are genetically determined by sex factors or conjugative plasmids and are required for bacterial mating Receptors of some bacterial viruses

1. The B-DNA structure found in solution is a A right-handed double helix of antiparallel chains (11 bp/turn) B left-handed double helix of antiparallel chains (~10 bp/turn) C right-handed double helix of antiparallel chains (~10 bp/turn). D left-handed zig-zag helix of antiparallel chains(12 bp/turn)

Teaching Outline Pre-reading Questions Background Information Passage AnalySIs style and structure spelling word derivation language points useful expressions

Teaching Outline Background information Pre-reading questions Passage analysis Style and structure Spellings Word derivations Language points Useful expressions Weekly quiz