steadfast
释义： 形容词，表“坚定的，不变的，不动摇的”，在留学文书中可以作为certain和dedicated的同义词进行替换，达到丰富词汇的目的。
例句：
Egypt is a steadfast ally in the GWOT global war on terror, and we maintain close cooperation on a broad range of counter-terrorism and law enforcement issues.
For his steadfast commitment to the letter and spirit of such aims, the president was awarded the Nobel Peace Prize only nine months after taking office.