'Lo' in the Bible

I have seen all the works that have been done under the sun, and lo, the whole is vanity and vexation of spirit!

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.

I said in my heart, 'Pray, come, I try thee with mirth, and look thou on gladness;' and lo, even it is vanity.

and I have looked on all my works that my hands have done, and on the labour that I have laboured to do, and lo, the whole is vanity and vexation of spirit, and there is no advantage under the sun!

And I have turned, and I see all the oppressions that are done under the sun, and lo, the tear of the oppressed, and they have no comforter; and at the hand of their oppressors is power, and they have no comforter.

Lo, that which I have seen: It is good, because beautiful, to eat, and to drink, and to see good in all one's labour that he laboureth at under the sun, the number of the days of his life that God hath given to him, for it is his portion.

Lo, this only have I found, that God hath made man upright; but they have sought out many inventions.