Hi, Mike, I need to ask you a favor.

嗨，迈克，我想求你件事。

I know maybe you're a little short on cash. I can lend you some.

我知道你手头可能有点紧。我可以借你些钱。

重点讲解:

I know you might have a cash-flow problem.

I know maybe you're a little short on cash.

如何表达“手头有点紧”?用have a cash—flow problem语法上没错，其中 cash-flow就表示“资金流动”，但是这么表达稍显正式，老外在口语中常用be short on cash表示“手头没钱”。