Question

 (2011年溫州十校聯(lián)考)—Where is Lucy?

—I can’t say where she is，but she________have gone to meet her classmates，for they want to go to Sichuan to work as volunteers.

A．can                       B．should

C．must                     D．may

Answer 1

解析：選D�？疾榍閼B(tài)動(dòng)詞。這里表示對(duì)過(guò)去狀況的推斷，故用“情態(tài)動(dòng)詞＋have done”。從前面的“我不確定她在哪里”可知，用may have done，表示“過(guò)去可能已經(jīng)做了……”(不確定)。must have done表示“過(guò)去一定做了……”(非常確定)；can have done主要用在否定句和疑問(wèn)句中；should have done表示“過(guò)去本該做……(實(shí)際卻沒(méi)做)”。