例1:The English teacher wants just one thing from us: that we try our best. (英語老師只希望我們做到一點:全力以赴。)
例2:May I offer you a suggestion: don't drive without your seat belts fastened. (給你一個建議:開車一定要系安全帶。)
2、承接因果
例1:I turned to look at the children, but there weren't any in sight: they had all run away. (我轉過頭去看那些孩子,他們卻全無蹤影:他們都跑光了。)
例2:We found the place easily: your directions were perfect. (我們找到這個地方毫不費力:你的導航太棒了。)
3、舉例或羅列
例1:There are only two tragedies in life: one is not getting what one wants, and the other is getting it. (人生的悲劇有兩種:一種是得不到自己想要的,一種是得到它。)
例2:For our camping trip, I brought various essential items: a lantern, a sleeping bag, food, water, and a flashlight. (關于露營,我帶了各種必備品:一盞燈,一個睡袋,食物,水,還有一個手電筒。)
4、用于引用
例1:The professor said: “It was horrible.”(教授說:“這太可怕了。”)
例2:In his most famous speech, he said: all men are created equal and must enjoy the equal rights that are given by God. (在他最著名的演講中,他說:人人生而平等,必須享受上帝賦予的平等權利。)
5、隔開正副標題
例1:Web Directory: World and Non-U.S. Economic Data(網絡目錄:世界與非美國經濟數據)
例2:Math Application: Using Calculus to Determine the Age of Rocks (數學應用:利用微積分測定巖石年齡)
6、用于正式信件的稱呼后(美式)
例1:Dear Mr. Lee: We were very honored to have you come visit our company. (親愛的李先生,非常榮幸您來我公司參觀考察)
7、表示時間
例1:The train is to leave at 4:45 pm. (火車下午4:45開)
8、表示比例
例1:The proportion of men to women is 3:5. (男女比例是3:5)