The abstract noun "conduct" can be translated with a verb. Alternate translation: "When you are with the Gentiles, you should always act in an honorable way" (See: [[rc://en/ta/man/translate/figs-abstractnouns]])
The abstract noun "deeds" can be translated with a verb. Alternate translation: "they may be eyewitnesses of the good things that you do" (See: [[rc://en/ta/man/translate/figs-abstractnouns]])
"on the day when he comes." This refers to the day when God will judge all people. Alternate translation: "when he comes to judge everyone" (See: [[rc://en/ta/man/translate/figs-explicit]])