你好！

sure 英[ʃʊə(r)] 美[ʃʊr]

adj. 确信的，确实的; 有把握的; 无疑的; 一定的;

adv. 当然; 确实地; 无疑地;

[例句]He'd never been in a class before and he was not even sure that he should have been teaching

他以前从未教过课，甚至不确定自己该不该教课。