【正确答案】Ambiguity occurs when one expression has more than one meaning. There are two types of ambiguity: lexical ambiguity and structural ambiguity. Obviously the reason why the sentence John saw a girl with a telescope is that the sentence has an ambiguous structure. This sentence can be interpreted either as "John had a telescope and through it he saw a girl" ("with a telescope" telling how John saw a girl) or "John saw a girl who had a telescope on hersel" ("with a telescope" modifying "a girl").
The ambiguity can be solved by the following two tree diagrams:
(1)
(2)

【答案解析】[解析] 本题主要考查句法学的相关内容，尤其是树形图的画法。考生一方面要对句法学的一些基本概念非常熟悉，同时又要熟练掌握树形图的画法。做到了这些，本题也就不难了。