【题目】_______ the difficult maths problem, she has consulted Professor Liu several times.
A. Worked out B. To work out C. Having worked out D. Work out
在线课程【答案】B
【解析】
考查不定式作目的状语。句意：为了算出这道数学题，她已经咨询了刘教授好几次了。根据句意可知句中的不定式to work out …表示目的。这也是不定式的主要用法之一，故B项正确。