关键 + 的 + Noun / 关键 + Noun
关键 (guānjiàn) means "key," "crucial," or "critical" and can function as both a noun and an adjective. As a noun it means "the key point" or "the crux," and as a modifier it means "key" or "vital." It is used to highlight the most important element in a situation.
时间管理是成功的关键。
Shíjiān guǎnlǐ shì chénggōng de guānjiàn.
Time management is the key to success.
这次考试的关键问题你都答对了吗?
Zhè cì kǎoshì de guānjiàn wèntí nǐ dōu dá duì le ma?
Did you answer all the key questions on this exam correctly?
团队合作在这个项目中起了关键作用。
Tuánduì hézuò zài zhège xiàngmù zhōng qǐ le guānjiàn zuòyòng.
Teamwork played a key role in this project.