问题补充：
to our study is the best way high grades.
A. Devote ourselves; to achieve
B. Devoting us; of achieving
C. Devoting ourselves; to achieve
D. Devoted ourselves; of achieving
答案：
A. Devote ourselves; to achieve
B. Devoting us; of achieving
(答案→)C. Devoting ourselves; to achieve
D. Devoted ourselves; of achieving
解析：考察非谓语动词用法。本题中的动词短语devote oneself to…致力于…；在本句中要使用动名词doing的形式做句子的主语。动词原形和过去分词是不能在句中做主语的。第二空是固定搭配the way to do sth/of doing sth做某事的方式。句义：努力学习是获得高分的唯一方法。故C正确。
