In English, we simply say "before the test" or "after the signal." In Turkish, the words for before (önce) and after (sonra) act as postpositions that require the preceding noun to take the ablative case (the "from" case).
Remember that the ablative case suffix is -dan or -den (changing to -tan or -ten after hard consonants).
Before (-den önce)
To say that an action happens "before [noun]", attach the ablative suffix to the noun and follow it with önce. Literally, you are saying an action happens "prior from" the noun.
| Before the test, the committee is waiting for you. | Sınavdan önce komisyon sizi bekliyor. |
| Be sure to slow down before the speed bump. | Kasisten önce mutlaka yavaşla. |
After (-den sonra)
To say "after [noun]", use the exact same structure but follow the ablative noun with sonra.
| Switch to first gear after the signal. | Sinyalden sonra birinci vitese geç. |
| Release the clutch slowly after the intersection. | Kavşaktan sonra debriyajı yavaş bırak. |
Time and Space
While we frequently use these structures for time and events (like an exam or a maneuver), -den önce and -den sonra are also used spatially to mean "before reaching [an object]" or "past [an object]".
This is especially helpful when giving driving directions, navigating streets, or following a physical sequence!
| Stop before the red car. | Kırmızı arabadan önce dur. |
| He is accelerating after the green light. | Yeşil ışıktan sonra hızlanıyor. |