'Understandest' in the Bible

What knowest thou, that we know not? What understandest thou, which is not in us?

Thou knowest my downsitting and mine uprising; Thou understandest my thought afar off.

Lo, I will bring a nation upon you from far, O house of Israel, saith Jehovah: it is a mighty nation, it is an ancient nation, a nation whose language thou knowest not, neither understandest what they say.

Jesus answered and said unto him, Art thou the teacher of Israel, and understandest not these things?

And Philip ran to him, and heard him reading Isaiah the prophet, and said, Understandest thou what thou readest?