段落文字可以进行如下哪些操作：

当将CMKY模式的图象转换为多通道时，产生的通道名称是什么（）

下列哪种格式支持图层：

若选择了前面的一个历史记录，在下列哪个选项被选中的时候，这个历史记录后面的历史记录不受影响：

Inthepast,operationsweredifficult.Untilthemiddleoftheeighteenfifties,surgerywasverydangerous.Manypatientsdiedaftereventhesmallestoperations.Thiswasbecausebacteriaenteredthecutsinthepatientsbodied’andstartedinfection.Insomecountries,upto90percentofpatientsdiedfrominfectionafteroperations.In1865,however,JosephLister,aBritishsurgeon,foundananswertotheproblem.Heusedan“antisepticduring”andafteroperations.Thiskilledthedangerousbacteriaandmostofhispatientslived.Sincethen,surgeonshaveusedantisepticsinalloperations.SurgeryhasdevelopedinmanyimportantwayssincethedayofJosephLister.Today,whenpatientsgotohospitalforanoperation,theycanexpectthebesttreatment,incleanandhygienicconditions.

33.Operationsweredifficultanddangerousuntil_______.

A.1850

B.themiddleof1850

C.themiddleofthefiftiesoftheeighteenthcentury

D.themiddleofthefiftiesofthenineteenthcentury

34.Inthepassage,surgerymeans__________.

A.Theperformingofanoperation

B.cure

C.treatment

D.medicine

35.Inthepast,upto90percentofpatientsdiedafteroperationsmainlyb

ecause__________.

A.bacteriaenteredthecutsinthepatientsbodies’andinfectiontookplace

B.theconditionsinhospitalswerebad

C.theskillofsurgeonswasnotsogood

D.therewerenogoodmedicineatthattime

36.Whichtopicofthefollowingbestsuitsthepassage?

A.Operationsweredifficultinthepast

B.ThedevotionofJosephListertomedicalscience

C.Surgeryhasbecomesafer

D.Developmentsinsurgery

37.JosephListerwas________.

A.aFrenchman

B.aGerman

C.anEnglishman

D.anAmeric