1. detect
2. find, discover, notice, sight, note
3. mention, remark, state, say, tell, note
4. take note, watch
5. respect
6. honor, honour, abide by, accept, celebrate
7. keep, watch
8. follow, watch over, keep an eye on, check, check up on, look into, check out, suss out, check over, go over, check into, keep
9. maintain, keep