RU-2

('ru' in the second tone)

There are 25 standard Chinese characters that can be spoken 'ru', though 'ru' may not be the principal pronunciation of all of them. The most common sound-determining element is 需, which itself is not even spoken as 'ru' but as 'xu(1)', and means to require. However, as sound-determining element i.n letters spoken 'ru', it occurs in a full eleven of them. Another rather complicated sound-determining component is: 辱 = ru(3) = to insult. It is present in five more characters that are also spoken 'ru', though not all of them in the same tone.

如 = if

But almost always, the two-character version is preferred.

如果 = ru(2)guo(3) = if

如何 = ru(2)he(2) = how