en_tn/ecc/08/09.md

I have applied my heart

Here the author refers to himself by his "heart" to emphasize his feelings. See how you translated this in Ecclesiastes 1:17. Alternate translation: "I applied myself" (See: rc://en/ta/man/jit/figs-synecdoche)

every kind of work that is done

This can be stated in active form. Alternate translation: "every kind of work that people do" (See: rc://en/ta/man/jit/figs-activepassive)

under the sun

This refers to things that are done on earth. See how you translated this in Ecclesiastes 1:3. Alternate translation: "on the earth" (See: rc://en/ta/man/jit/figs-idiom)

There is a time when a person oppresses another person to that person's hurt

"Sometimes one person will oppress another, causing that person to be hurt"