without, otherwise, but for, but引導(dǎo)的短語或句子有時相當(dāng)于一個虛擬條件句.假設(shè)的情況并不以條件從句表示出來,而是暗含在上下文中,通過介詞短語來表示.
使用到這些詞組的句子中,虛擬語氣的用法一般是：對現(xiàn)在的虛擬：would+do；對過去的虛擬：would(not) + have done.
比如：But for your reasonable advice,i wouldn't have fininshed my paper excellently.Without bring in him as the PM(project manager項目經(jīng)理)of our company,the important program would have failed.
I should study more hard,otherwise i would have kepet with the most outstanding sutdent in my class in last exam. Your mother would go with you,but she has to take care of your elder brother