See in Reader
1005 B
Look
The author uses this word here to draw his reader's attention to what he says next. Alternate translation: "Pay attention" or "Listen" (See: rc://en/ta/man/translate/figs-idiom)
what I have seen to be good and suitable
Here the words "good" and "suitable" mean basically the same thing. The second intensifies the meaning of the first. Alternate translation: "what I have seen to be the best thing to do" (See: rc://en/ta/man/translate/figs-doublet)
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/translate/figs-idiom)
during the days of this life that God has given us
This is an idiom. Alternate translation: "as long as God allows us to live" (See: rc://en/ta/man/translate/figs-idiom)
For this is man's assignment
Possible meanings are 1) "For this is man's reward" or 2) "For these are the things that he allows man to do"