269.Barack Obama's victory is a historic victory an _____ that promised change and overcame centuries of prjudice.
A.one
B.it
C.the one
D.that
270.One of the most important questions they had to consider was _____ of public health.
A.what
B.this
C.that
D.which
269.答案是A；此处one指代a historic victory。
270.答案是C；that指代上文的the+名词，即the question.
