A 不定式用在only后面时，常表示一种令人失望的后果：He hurried to the house only to find that it was empty．他急忙赶到那所房子，却发现空无一人。相当于：He hurried to the house and was disappointed when he found that it was empty．他急忙赶到那所房子，但发现房子空无一人时感到大为失望。he survived the crash only to die in the desert．相当于：He survived the crash but died in the desert．飞机坠毁时他幸免于难，后来却死在沙漠里。B 不定式前不加 only也可以起连接作用，并且不带有不幸的含义：He returned home to learn that his daughter had just become engaged．他回到家里，得知女儿才订了婚。但这类用法主要限于如 find， hear， learn，see， be told这类动词，否则用于起连接作用的不定式就可能被错认为是表示目的的不定式。