(1)一(必)定，肯定(without any doubt;definitely)： He will～come.他肯定會(huì)來(lái)。She is～pretty.她當(dāng)然漂亮。I～wish them victory.我當(dāng)然希望他們?nèi)〉脛倮??！纪絪urely;
(2)當(dāng)然(yes;of course)(用于回答問(wèn)題)：“Can I try it on?” “C～(=Yes).”“我可以試穿一下嗎?”“當(dāng)然可以?！薄癆re you paying for him?” “C～not(=No，definitely not).”“你是在替他付錢嗎?”“當(dāng)然不是。”
【辨異】certainly與surely語(yǔ)義相近，但有區(qū)別。當(dāng)確知真相時(shí)用certainly，當(dāng)僅僅是有強(qiáng)烈的希望和信念時(shí)，用surely，如：He certainly didn't steal the money.I stole it myself.(他肯定是沒偷那錢。是我自己偷的。)Surely he didn't steal the money. He's not that kind of person.(當(dāng)然他沒偷那錢。他不是那種人。)此外，在回答問(wèn)題時(shí)，BrE中用certainly(見(2))，AmE中則用 surely(或 sure)，如：“Can I try it on?”“Sure(ly).”“我可以試穿一下嗎?”“當(dāng)然?！?/p>