【正确答案】：
ENGLISH HAS A LARGE NUMBER OF WORDS SUCH AS NOW/THEN, HERE/THERE, I/YOU, THIS/THAT, WHICH ARE OFTEN 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 PERSON MOMENT IF THE PERSON IS SPEAKING. IT IS THE SAME WITH ALL REFERRING EXPRESSIONS. EVEN A PHRASE LIKE THE PRIME MINISTER MAY BRING ABOUT AMBIGUITY WITHOUT ADEQUATE VERBAL CONTEXT, FOR IT CAN BE USED TO REFER TO ANY OF THE PRIME MINISTERS IN BRITISH HISTORY. 
【题目解析】：英语中有大量的单词，如“现在/那时”、“这里/那里”、“我/你”、“这个/那个”，这些单词经常被用来直接指代人、时间、地点等。如果没有清晰的上下文，所指物可能会非常混乱。例如，“现在”这个词总是指说话的时间，自然地指的是过去的演讲发生在过去的时间，或者指的是某人讲话的时间。所有所指的词用法都是相同的。即使是像首相这样的词组，在没有足够的语言语境的情况下也可能产生歧义，因为它可以用来指代英国历史上的任何一位首相。