'Burden' in the Bible

I applied my heart to seek and to search out by wisdom concerning all that is done under the sky. It is a heavy burden that God has given to the sons of men to be afflicted with.

I have observed the burden that God has given to people to keep them occupied.

There exists another misfortune that I have observed on earth, and it is a heavy burden upon human beings:

This is what I also observed about wisdom on earth, and it is a great burden to me:

Also when they shall be afraid of that which is high, and fears shall be in the way, and the almond tree shall flourish, and the grasshopper shall be a burden, and desire shall fail: because man goeth to his long home, and the mourners go about the streets: