今天小编给大家带来2019年大学英语六级语法知识：非真实条件句，希望对大家有所帮助。

英语六级语法知识：非真实条件句

时态：可以表示过去，现在和将来的情况。它的基本特点是时态退后。

a.同现在事实相反的假设。

句型：条件从句主句

一般过去时should(would)动词原形

Iftheywerehere,theywouldhelpyou.

b.表示于过去事实相反的假设。

句型：条件从句主句

过去完成时should(would)have过去分词

Ifshehadworkedharder,shewouldhavesucceeded.

Thericewouldnothavebeenburntifyouhadbeenmorecareful.

IfmylawyerhadbeenherelastSaturday,hewouldhavepreventedmefromgoing.

Ifhehadcomeyesterday,Ishould/wouldhavetoldhimaboutit.

含义：Hedidnotcomeyesterday,soIdidnottellhimaboutit.

Ifhehadnotbeenillandmissedmanyclasses,hewouldhavemadegreaterprogress.

含义：Hewasillandmissedmanylessons,sohedidnotmakegreaterprogress.

c.表示对将来的假想

句型：条件从句主句

一般过去时should动词原形

were不定式would动词原形

should动词原形

Ifyousucceeded,everythingwouldbeallright.

Ifyoushouldsucceed,everythingwouldbeallright.

Ifyouweretosucceed,everythingwouldbeallright.