单选题 It was not until almost a century ______ blacks began to demand their rights as American citizens.

【正确答案】 C
【答案解析】此句考查强调句型。强调句型的基本结构为“It is (was)... that (who)...”，其中句子为过去时态时用was，强调主语时用who。此句意为“直到将近一个世纪之后，黑人才开始要求他们作为美国公民的权利”。