K E I C H I

quid pro quo:

1. (law) this for that; giving something to receive something else
2. an equal exchange

   We had no money so we had to live by quid pro quo.

3. something equivalent
4. something in return

ipso facto:

1. By that very fact itself. Compare: eo ipso.

“if two individuals fail to make an exchange, then this ipso facto demonstrates that at that moment at least one of them would not have benefited from the exchange.”

—Bryan Caplan, “The Austrian Search for Realistic Foundations”

ergo:

1. therefore
2. because
3. hence
4. consequently

rectum:

1. from Latin rectus (meening straight).

翻譯很難 不過查單字很容易(相對來說)