Itissupposedtoraintoday.
besupposedto的用法
用法一：besupposedto...其中to是动词不定式符号,不是介词,其后要跟动词原形.当besupposed
to...的主语是“人”时,意为“应该……
”；“被期望……”,它可以用来表示劝告、建议、义务、责任等,相当于情态动词should.如：
Everyoneissupposedtowearaseat-beltinthecar.
每个人在汽车里都应该系安全带.
Teachersaresupposedtotreatallthestudentsalike.
老师应该对所有的学生一视同仁.
用法：当besupposedto...的主语是“物”时,它表示“本应；本该”,用于表示“某事本应该发生而没有发生”.如：
Thenewlawsaresupposedtopreventcrime.这些新法令本应该起到防止犯罪的作用.
Thetrainwassupposedtoarrivehalfanhourago.火车本应在半小时之前到达.
用法三：besupposedto后面接“have+过去分词”时,表示“本应该做某事而没做”.如：
Youaresupposedtohavehandedinyourhomeworkbynow.
现在你应该已经把作业交上来了.
Heissupposedtohavearrivedanhourago.他应该一小时前就到了.
用法四：besupposedto...的否定结构为benotsupposed
to...,它常用于口语中,意为“不被许可；不应当”.如：
Shewasnotsupposedtobeangryaboutthat.她本不该为那件事而生气的.
Youarenotsupposedtosmokeonthebus.你不应该在公共汽车上吸烟.
