意义：用于阐述事实.x0d结构：If+subject+simplepresent,subject+simplepresent.x0dSubject+simplepresentif+subject+simplepresent.x0d例句：IfIseeaspider,Igetpanicky.x0dIfeelclaustrophobicandimmediatelywanttogetoutofifIenteranenclosedspace.x0d第一条件句FirstConditionalx0d意义：表达一个动作后的结果x0d结构：If+subject+simplepresent,subject+will+verb.x0dSubject+will+verb+if+subject+simple+present.x0d例句：Ifwemovetheofficetothe15thfloor,I'llresign.x0dI'llprobablyhaveanotherpanicattackifIseeaspider.x0d第二条件句SecondConditionalx0d意义：用于表达一个假设情况后的结果.x0d结构：If+subject+simplepast,subject+would+verb.x0dSubject+would+verb+if+subject+simplepast.x0d例句：IfIdidn'tsufferfromafearofflying,Iwouldtravelmore.x0dIwouldconsultadoctorifIhadaphobia.x0d第三条件句ThirdConditionalx0d结构：If+subject+pastperfect,subject+wouldhave+pastperfect.x0d改成第三条件句：Ifshehadn'tbeenill,shewouldhavegonetowork.