選A.原句是It is important that we should get this message across to voters.這里是虛擬語氣的一個(gè)用法之一. 只不過should 可以省略的.怎么判斷是虛擬語氣呀這里是虛擬語氣的一些特例。 表情緒.觀點(diǎn)的形容詞或名詞也要用虛擬語氣.如：necessary、important、impossible、natural、strange、surprising、funny、right、wrong、better、a pity ,the shame ,no wonder等。　　句型：It is.......that +主語從句，從句的謂語動(dòng)詞都要用 should+原型或 只用動(dòng)詞原型?！　g:　　Do you think it is necessary that he (should)not be sent to Lingbao.　　It is strange that such a person should be our friend. 　一想要( desire ) 一寧愿( prefer ) 一堅(jiān)持( insist )二命令( order , command ) 三建議( advise , suggest , propose/recommend) 四要求( demand , require , request , ask)中，無論主句謂語動(dòng)詞為何種時(shí)態(tài)，從句的謂語動(dòng)詞都用："should + do"。should可以省略。　　eg：He suggested that we (should) take the teacher's advice.　　He insisted that we (should) take the teacher's advice.　　He demand that we (should) take the teacher's advice.　　He ordered that we (should) take the teacher's advice. 虛擬語氣還可用在定語從句中，表示：“早該做某事了”時(shí)，定語從句中的謂語動(dòng)詞須用虛擬語氣，其虛擬語氣的結(jié)構(gòu)為：It is (high / about) time that + 主語+ 動(dòng)詞的過去式/ should + do（優(yōu)先使用動(dòng)詞過去式） ，即從句用虛擬過去式。