It is supposed to rain today.
be supposed to 的用法
用法一： be supposed to... 其中to是動(dòng)詞不定式符號(hào),不是介詞,其后要跟動(dòng)詞原形.當(dāng)be supposed
to... 的主語是“人” 時(shí),意為“應(yīng)該……
”；“被期望……”,它可以用來表示勸告、建議、義務(wù)、責(zé)任等,相當(dāng)于情態(tài)動(dòng)詞should.如：
Everyone is supposed to wear a seat-belt in the car.
每個(gè)人在汽車?yán)锒紤?yīng)該系安全帶.
Teachers are supposed to treat all the students alike.
老師應(yīng)該對所有的學(xué)生一視同仁.
用法：當(dāng)be supposed to... 的主語是“物”時(shí),它表示“本應(yīng)；本該”,用于表示“某事本應(yīng)該發(fā)生而沒有發(fā)生”.如：
The new laws are supposed to prevent crime. 這些新法令本應(yīng)該起到防止犯罪的作用.
The train was supposed to arrive half an hour ago. 火車本應(yīng)在半小時(shí)之前到達(dá).
用法三： be supposed to后面接“have + 過去分詞”時(shí),表示“本應(yīng)該做某事而沒做”.如：
You are supposed to have handed in your homework by now.
現(xiàn)在你應(yīng)該已經(jīng)把作業(yè)交上來了.
He is supposed to have arrived an hour ago. 他應(yīng)該一小時(shí)前就到了.
用法四： be supposed to... 的否定結(jié)構(gòu)為be not supposed
to...,它常用于口語中,意為“不被許可；不應(yīng)當(dāng)”.如：
She was not supposed to be angry about that. 她本不該為那件事而生氣的.
You are not supposed to smoke on the bus. 你不應(yīng)該在公共汽車上吸煙.