问题
选择题
Last term our maths teacher set so difficult an examination problem _____ none of us worked out.
A．that
B．as
C．so that
D．which
答案
答案：B
as引导定语从句修饰"examination problem",在从句中作宾语,因其先行词前有限定词so。若看作"so…that…"结构,结果状语从句应加宾语,为"worked it out"。