en_tn/ecc/03/16.md

I have seen the wickedness ... wickedness was there

These two phrases mean the same thing and emphasize how common wicked behavior is. (See: rc://en/ta/man/translate/figs-parallelism)

in place of righteousness

"where there should be righteousness"

under the sun

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

I said in my heart

Here the author refers to himself by his "heart" to emphasize his feelings. AT: "I said to myself" (See: rc://en/ta/man/translate/figs-synecdoche)

the righteous and the wicked

This refers to righteous and wicked people. AT: "those who are righteous and those who are wicked" or "the righteous people and the wicked people" (See: rc://en/ta/man/translate/figs-nominaladj)

every matter and every deed

These two phrases mean basically the same thing and refer to every action that people do. (See: rc://en/ta/man/translate/figs-doublet)