can及could與不定式完成式連用(have+過去分詞)都表示對過去某事的猜測。can只能用於疑問句和否定句之中。 Where can she have gone?她會上哪兒去了呢? She can’t have gone to school——it’s Saturday.她不可能是去上學了,今天是星期六。 She could have gone off with some friends .她可能是和幾個朋...