??? 情景例句
John cannot get to the phone right now.
John現在沒辦法接電話。
I cannot be your friend and your flatterer too.
我不能既是你的朋友，而又對你阿諛奉承。
and at the most critical juncture we took turns in watching that point.
在最緊急的時刻，我們輪流監視那段河流的險情。