These are all words describing sth that will definitely happen or is definitely true. 以上各词均指某事肯定、必定会发生或属实。

• certain that you can rely on to happen or be true 指确实、确定、肯定（会发生或是事实）：◆It's certain that they will agree. 他们肯定会同意。◆They are certain to agree. 他们肯定会同意。
• bound [not before noun] certain to happen, or to do or be sth 指肯定会、一定会 NOTE Bound is only used in the phrase bound to do/be, etc. * bound 只用于 bound to do/be 等短语中：◆There are bound to be changes when the new system is introduced. 新系统引进后肯定会有变化。◆You've done so much work—you're bound to pass the exam. 你下了这么大功夫，一定能通过考试。
• sure certain to happen or be true; that can be trusted or relied on 指必定、无疑（会发生或是事实）或不容置疑、确切、可靠：◆She's sure to be picked for the team. 她肯定会入选该队。◆It's sure to rain. 一准会下雨。
• definite (rather informal) certain to happen; that is not going to change 指必将发生、不会改变：◆Is it definite that he's leaving? 他肯定要离开吗？
• guaranteed certain to have a particular result 指肯定会、必定会（有特定结果）：◆That kind of behaviour is guaranteed to make him angry. 那样的行为肯定会让他生气。

Patterns

• certain/sure of sth
• certain/bound/sure/guaranteed to do sth
• certain/definite that…
• I couldn't say for certain/sure/definite.