One of the things to be learnt in a foreign language is guessing all the time what kind of thing to come when listening to someone talking. People do this all the time in their own language, so it is necessary ( 必要的 ) to do this in a foreign language, too. Here are some examples. 1. "What's the matter ? " "I went to a party last night, so I..." 2. "I feel so tired these days."" I think you'd better..." 3."Of course, she never stops talking. She is one of the most..." You can see from the above three examples that the context ( 上下文 ) helps a lot in understanding what is being talked about. So "guessing "is very important in understanding English, especially ( 尤其 )spoken English.