单选题 It is still not clear what ______ a series of argument between them.
A. contributed B. marked C. ignited D. triggered

【正确答案】 D

【答案解析】[解析] 本题空格处是说引发一系列的争论。D项“triggered引发，触发”符合题意。如：a high-level meeting that triggered bitter bureaucratic debates．(一个引发了激烈的官僚政治论争的高级会议。)其他三项“contributed捐献；marked标记；ignited点火，使激动”都不正确。