Important 這個形容詞與介系詞連用時，通常接for, in 或 to：Winning the game yesterday was important for the team’s morale. (贏得昨天那場比賽對鼓舞全隊的士氣至關重要)；Information and support are important in helping people deal with swine flu. (資訊和支援對幫助人們對抗豬流感是很重要的)；Your interest and support are important to your child. (你的興趣與支持對你的孩子很重要)。
Important 也可接帶 to 的不定詞和 that 子句：It is important to learn to communicate. (學會溝通很重要)；It’s important that he (should) learn to read. (他學會閱讀是很重要的) — 「It + be 動詞 + essential, important, necessary, vital 等形容詞 + that + S (should) V…」是一種用來表示命令、要求、建議或堅持的常見句型，如 It is important that he be sent there at once. (馬上派他去那裡是很重要的)，但必須注意的是，由於 should 的關係，that 子句中的主動詞一律用原形動詞。若是最高級，important 通常與 of 連用：She was the most important of all the contestants. (她是所有參賽者當中最重要的)。
無論是形容詞 more/most important 還是副詞 more/most importantly 都可當句子副詞 (sentence adverb)，且都是標準用法：More [Most] important [importantly], we now have the right answer. (比較重要的是/最重要的是，我們現在有了正確的答案)。