一定的英文：
surely
certainly
necessarily
fixed
a certain (extent, etc.)
given
particular

• The new show is certainly pulling in the crowds.
  新的表演一定很吸引人。
• Make sure the top is screwed back tightly onto the jar.
  一定要把罐子盖拧紧。
• I'll help you insofar as I can.
  我一定尽力帮助你。
• The party on Saturday night is going to be awesome. Booyah!
  周六晚上的聚会一定很棒，哦耶！
• You must copy it fair.
  你一定要把它抄写清楚。
• To wander from a set course or point of attention; stray.
  离开一定的路线或注意点;游离
• Take his vital signs at regular intervals.
  每隔一定时间检查他的生命体征。
• A lady who is house-proud must also like to keep open house.
  一个讲究家里摆设的女人也一定很好客。
• The effective permeability is stated as some numerical value at some given saturate conditions.
  有效渗透率用在一定饱和条件下的数值表示。
• He must have hit the jackpot with the sales of his last gramophone record.
  他卖掉最后的一张留声机唱片，一定赚了大钱。

• brassard: "Sure, sure."
  布拉萨尔:“当然，当然。”
• Make sure you get there in time.
  一定要准时到达那里。
• Be sure not to let the truth slip.
  千万别把真相泄漏出去。

• You are certainly a profiteer.
  你真是个奸商。
• That ring is certainly the cheese.
  那只戒指无疑是精品。
• You are certainly a talented artist.
  你当然是位有天赋的艺术家。