单选题 ______hard he had worked on his math, he did not seem to make much progress.
【正确答案】 C
【答案解析】解析：句意：不管他学数学多么努力，看起来他都没有多大起色。no matter how或者是however后加形容词或副词，表示“无论多么”，从句需部分倒装。