倒票的英文：
speculative reselling of tickets

参考例句：

He was trying to pick up some cash scalping tickets.
他那时正想通过倒票赚点儿钱。

speculative是什么意思：
adj. 推测出的；投机的

He ventured on a rash speculation.
他进行鲁莽的投机。

His conclusions are purely speculative.
他做出的结论纯粹是推测而来的。

Every induction is a speculation.
所有归纳推理都是一种猜测。

tickets是什么意思：
n. 票，券；标签；证明书，许可证，执照；传票；传票，罚单
v. 加票签于；指派；对...开罚单（或传票）

Admission by ticket only.
凭票入场。

This is your discharge ticket.
这是你的解雇证明书。

The admission ticket is flat.
门票费是统一的。