Concordant Literal Version:
Ecc 1:13 I applied my heart to inquiring and exploring by wisdom concerning all that is done under the heavens: it is an experience of evil Elohim has given to the sons of humanity to humble them by it.
Ecc 1:14 I have seen all the works that are done under the sun; and, behold, all is vanity and vexation of spirit.
Ecc 1:15 That which is crooked cannot be made straight: and that which is wanting cannot be numbered.
Ecc 1:16 I communed with mine own heart, saying, Lo, I am come to great estate, and have gotten more wisdom than all they that have been before me in Jerusalem: yea, my heart had great experience of wisdom and knowledge.
Ecc 1:17 And I gave my heart to know wisdom, and to know madness and folly: I perceived that this also is vexation of spirit.
Ecc 1:18 For in much wisdom is much grief: and he that increaseth knowledge increaseth sorrow.