大学英语ppt课件.pptx

;Devastation?by?El?Nino—a?Warning?? 厄尔·尼诺现象将带来毁灭 一则警告;When?these?headlines?appeared?this?year,?their?stories?became?the?subjects?of?conversations?around?the?world?talks?spiced?with?optimism?and?confusion.?Imagine?the?hopes?raised?in?the?millions?battling?cancer.?Did?the?news?mean?these?people?never?had?to worry?about?cancer?again? Or?that?we?all had?to?worry?about?a?catastrophe?from?outer?space?or,?more?immediately,?from?El?Nino? ;;But ;Unfortunately,?science?doesn't?work?that?way.?It?rarely arrives?at?final?answers.?People?battling cancer?or?victims? of?El?Nino?may?find?this?frustrating,?but?the?truth?is?that?Nature?does?not?yield?her?secrets?easily.?Science?is?done?step?by?step.?First?an?idea?is?formed.?Then?this?is?tested?by?an?experiment. The?outcome,?one?hopes,?results?in?an?increase?In knowledge.??;Science?is?not?a?set?of?unquestionable?results?but?a?way?of?under?standing?the?world?around?us.?Its?real?work? is?slow.?;The?scientific?method,?as?many?of?us?learned?in?school,?is?a?gradual?process?that?begins?with?a?purpose?or?a?problem?or?question?to?be?answered.?It?includes?a?list?of?materials,?a?procedure? to?follow,?a?set?of?observations?to?make?and,?finally,?conclusions?to?reach.?In?medicine,?when?a?new?drug?is?proposed?that?might?cure?or?control?a?disease,?it?is?first?tested?on?a?large?random? group?of?people,?and?their?reactions?are?then?compared?with?those?of?another?random?group?not?given?the?drug.?All?reactions?in?both?groups?are?carefully?recorded?and?compared,?and?the?drug?is?evaluated.?All?of?this?takes?time—and?patience.?? ;It's?the?result?of?course,?that?makes?the?best?news?─not?the?years?of?quiet?work?that characterize?the?bulk?of?scientific?inquiry.?;After?an?experiment?is?concluded?or?an?observation?is?made,? the?result?continues?to?be?examined?critically. ? When ?it is?submitted?for?publication,?it?goes?to?a?group?of?the?scientist's?colleagues,?who?review?the?work.?If?the?work?is?important enough,?just?before?the?report?is?published?in