I want to thank you for placing such a big order with us. You won't be disappointed.

谢谢你下了这么大的订单，你一定不会失望的。

I'd like to buy some stamps for this letter.

我想买这封信的邮票。

I'd like to cash some traveller's checks here.

我想在这儿兑换一些旅行支票。

There are several tours of the Grand Canyon.

到大峡谷有好几个旅游团。

Sure. Would you please sign your name on the back, sir, with your passport number?

每问题。先生，请您在支票背后签上名字和护照号码。

By all means, you ahead.

当然可以。随便。