“前提是……” 怎么说

前提是 -- the premise is that 或：the precondition is that

我会跟你走，前提是，你兑现你的承诺
I'll follow you,but the premise is that you should fulfil your promise.

或：I'll go with you,but the precondition is that you should carry out your promise.

premise: [ 'premis ]

我会跟你走，前提是，你兑现你的承诺

I will go with you, but the precondition is that you keep your promise.

前提是: the precondition is

我会跟你走，前提是，你兑现你的承诺
I will go with you on the premise that you will carry out your promise.