A black car rushed around the busy street corner, towards the courthouse. The dark       window rolled down and a semi-automatic        stuck out.

   Pauly Gillespie, a government protected witness (目击者), stood      , seeing death walking toward him. Pauly’s FBI bodyguards       themselves on top of him, but two     were fired and Pauly was hit       the shoulder.

   The car       across two lanes (车道) of traffic. Then it turned left down a path and got __    behind a large truck. The two men in the car       out and raced away ---      into the arms of four policemen.

         Special agent (特工) Brown was new to the police unit and was told to    __ the car out of the path so that the traffic could return to      . Brown changed the position of the rearview (后视) mirror     _ and drove it around to    __ his boss was questioning the two men.

   Brown stood and watched. One of the men was tall and thin, and     _ was five inches shorter, about Brown’s      .

Agent Fordney asked the two men who had done the shooting. They    __ to tell him. Then Brown smiled and said, “I know who the shooter was.” His boss was surprised. How could Brown know that without getting any answer from the two men?

When Brown got into the car, he had to adjust the rearview mirror. That meant the previous driver had been of a       height. Since the shorter man was close to Brown’s height, he knew the taller man must have been the     _. Therefore, the shorter man had done the      .

1.A. driver-side          B. passenger-side      C. right-hand side      D. left-hand side

2.A. hand           B. camera C. handgun                 D. knife

3.A. frozen        B. calm               C. quiet              D. still

4.A. put              B. rushed           C. jumped          D. threw

5.A. bullets      B. shots              C. guns               D. shoots

6.A. on             B. at           C. over               D. in

7.A. sped  B. rolled             C. moved           D. went

8.A. damaged    B. destroyed     C. stuck              D. injured

9.A. came          B. hurried C. walked         D. crawled

10.A. suddenly B. right               C. quickly         D. immediately

11.A. clear                  B. ride                C. carry              D. push

12.A. common  B. ordinary        C. usual              D. normal

13.A. up             B. down              C. in           D. out

14.A. where      B. there              C. which                    D. what

15.A. another   B. other              C. the other                D. one

16.A. size           B. length            C. age                 D. height

17.A. decided   B. refused         C. had               D. pretended

18.A. same        B. large               C. different        D. small

19.A. murderer         B. shooter          C. driver             D. killer

20.A. killing       B. shooting        C. driving           D. murdering

 

　　Atoms are building materials of all matter, because by putting together atoms in different ways, all elements and compounds can be formed．

　　An element is a substance or a kind of thing that has only one type of atom． Pure oxygen has only oxygen atoms． Elements are substances which cannot be broken down chemically into any simpler substances．

　　All the atoms of an element have the same atomic number． You will remember that the atomic number is the number of protons (= very very small pieces of matter that carry positive or Å electricity) in the nucleus or centre of an atom, and this number determines or decides the nature of the element． Each oxygen atom has eight protons in its nucleus, while each aluminum has thirteen． We call these substances elements because all their atoms are of the same type;they all have the same number of protons in the nucleus．

　　The element is made up of chemical units which have two or more atoms held together by chemical bonds or connections． A chemical unit is the smallest unit of a substance which shows all the chemical nature of the substance． Chemical units of elements are called molecules． The number of atoms in a molecule depends on the element．

　　At room temperature, some elements are gases (in a gas, there are larger spaces between the (molecules )． In the Noble Gases, each molecule has only one atom, because the atoms of these elements do not form chemical bonds with each other． In other gases, however, the molecules each have two atoms held together by chemical bonds． For example, nitrogen, chlorine, fluorine, oxygen, and hydrogen are all gases whose molecules have two atoms each．

　　The chemical symbol or sign of an element stands for one atom of the element． The formula of the element, however, stands for one molecule of the element．

　　Most elements are solid at room temperature． Some of these elements are made up of single atoms placed closely together within the solid, e．g． copper, iron, and nickel．

　　Other solid elements are made up of molecules with two or more atoms each． Iodine is a solid whose molecules have two atoms each(I2 ), but phosphorus has molecules made up of four atoms (P4 ), while the molecules of sulphur may have up to eight atoms each ( S8 )． In each of these elements, the molecules are put so closely together that the result is a solid substance．

　　Bromine and mercury are two elements which are liquids at room temperature． Bromine, like its neighbours chlorine and iodine in the periodic ( = of period ) table, has molecules made up of two atoms each． In these liquid elements, the molecules are close together, but not so crowded;they can pass lightly by one another．

1．All elements are made up of　　　　 ．

A．atoms B． matter C． building materials D． molecules

2Pure elements can ______．

A．never be broken away in any way

B．not be broken into smaller parts in any simpler way

C．seldom be made up of only one atom

D．have only oxygen atoms

3．Which of the following statements is TRUE?

A．The nature of atoms decides the nature of an element they are in．

B．The number of atoms decides the nature of an element they are in．

C．The nature of protons inside an atom decides the nature of the atom．

D．The number of protons inside an atom decides the number of the atom．

4． The symbol of aluminum is ______ and its atom number is ______

A．Al, 8 B．Alu, 9 C．Al, 13 D．Alu, 14

5． The molecule is ________of a substance．

A．a small chemical unit B．the smallest unit

C．the chemical bonds　　D．a chemical unit

6． A noble gas molecule has ________．

A．something to do with room temperature

B．no chemical bonds with each other

C．only one atom

D．has no chemical bonds with other elements

7．The formula of fluoride , sulphur , iodine and phosphorus are __________．

A 2, 4, 6, 8 B．2, 2, 4, 8

C．2, 4, 2, 8 D．2, 8, 2, 4

8． Molecules in a solid are 　　 those in a gas．

A．as closely placed as B．more closely put than

C．less closely placed than D．smaller in space than

9． It seems that elements in an ordinary lab are 　　 solids．

A．mostly B．sometimes C．seldom D．never

10． Which of the following statements is TRUE?

A．Bromine and mercury are always solids．

B．Molecules of liquids are less closely put than those of gases．

C．Each bromine element has the same number of atoms as that of nitrogen．

D．Liquid molecules are always more closely put than those of solids．