问题
选择题
The math problem was _________ difficult __________ none of us worked it out.
A．very; that
B．too; to
C．so; that
D．enough; that
答案
答案：C
题目分析：句意：这道数学题太难了以至于我们中谁也做不出来。so...that...如此……以至于……；too...to...太……而不能,to后接动词。故选C.