事实上，只须两个字母就已经足够：delta和eta。

Actually, just two letters will do: delta and eta.

youdao

什么字由五个字母组成，减去两个字母只余一？

What word of five letters has only one left when two letters are subtracted?

youdao

什么字由五个字母组成，减去两个字母只余一？

What word of five letters has only one left when two letters are subtracted?

youdao