问题：
How do you account for the context function as ind
答案：
English has a large number of words such as now/then, here/there, i/you, this/that, used to refer directly to people， time， place， etc. without clear context， the reference can be very confusing. For example the word now always means the time of speaking, naturally referring to a past time when the speech took place in the past or a present moment if the person is speaking. It is the same with all referring expressions. Even a phrase like the Prime Minister may bring about ambuiguity without adequent verbal context, for it can be used to refer to any of the Prime Minister in British history.