Romanian writes sau for the conjunction meaning or. It writes s-au when the unstressed short form s- of se joins the third-person plural auxiliary au in the compound past. Compare Vrei ceai sau cafea? (Do you want tea or coffee?) with S-au întors devreme. (They came back early.)
How do you choose between sau and s-au?
Write sau as one word when it connects alternatives. Write s-au with a hyphen when the unstressed short form s- of se joins the third-person plural auxiliary au before a past participle.
- Ask whether the sentence offers a choice. If the form means or, choose sau: Stăm acasă sau ieșim? (Are we staying home or going out?).
- If the sentence describes what they did or what happened to them in the past, look for the auxiliary au followed by a past participle, such as întors, trezit, or întâlnit.
- When that verb also needs the short form of se, write the two parts as s-au, with no spaces around the hyphen: S-au întâlnit la gară. (They met at the station.).
When is sau one word?
Use sau whenever one option is set against another option, whether the alternatives are nouns, phrases, or whole clauses. It does not describe an action and it never needs a hyphen in this use. See coordinating conjunctions for the wider choice pattern.
- Between nouns: Preferi mere sau pere? (Do you prefer apples or pears?).
- Between prepositional phrases: Mergem cu trenul sau cu autobuzul? (Are we going by train or by bus?).
- Between clauses: Învățăm acum sau facem o pauză? (Are we studying now or taking a break?).
When is s-au hyphenated?
Use s-au in perfectul compus when the short form s- of se comes before the auxiliary au. The hyphen joins the short form to the auxiliary; the main verb remains a separate past participle. See the Romanian compound past for the full tense, and compare Romanian hyphen patterns and hyphens with unstressed pronouns and auxiliaries for the spelling pattern.
| Written form | Verb parts | Meaning |
|---|---|---|
| S-au întors. | s- + au + întors | They came back. |
| S-au trezit devreme. | s- + au + trezit | They woke up early. |
| S-au întâlnit la gară. | s- + au + întâlnit | They met at the station. |
The form s-au does not mean or. In these examples, s- belongs to the verb construction, and au marks the third-person plural compound past. The exact role of se depends on the verb: it can be reflexive or reciprocal, as in s-au întâlnit (they met).
Which spelling mistakes change sau or s-au?
- Do not write s-au in a choice: write Vrei supă sau salată? (Do you want soup or salad?).
- Do not split the past-tense form: write S-au mutat în Cluj. (They moved to Cluj.), not a form with a space between s and au.
- Do not attach the past participle to the auxiliary: write S-au întors, with întors as a separate word.
- At the beginning of a sentence, distinguish Sau alegem altceva? (Or shall we choose something else?) from S-au întors. (They came back.) The capital letter is not the test; the meaning and verb structure are.
Which sentence uses sau to offer a choice?
- S-au întors devreme.
- Vrei ceai sau cafea?
- S-au întâlnit la gară.
- S-au trezit la șapte.
Sau means or and joins the two choices ceai and cafea. The other sentences use s-au as part of a third-person plural compound-past verb.
Which sentence correctly says that they came back early?
- S-au întors devreme.
- Sau întors devreme.
- S au întors devreme.
- Său întors devreme.
The compound-past verb needs s-au: the short form s- joins the auxiliary au, while întors stays separate. Sau is the conjunction, and său is a different word.
Complete the choice question: Mergem la munte ___ la mare?
- și
- dar
- s-au
- sau
The sentence asks the listener to choose between two destinations, so the conjunction sau is required. The hyphenated s-au is a verb form, not a choice marker.
Which sentence is spelled correctly?
- Copiii sau întors acasă.
- Copiii s-au întors acasă.
- Copiii său întors acasă.
- Copiii s au întors acasă.
In Copiii s-au întors acasă, s- and the auxiliary au are joined by a hyphen. The other options omit the hyphen, use the possessive word său, or insert a space inside the form.
Which rule distinguishes sau from s-au?
- Use sau for an alternative and s-au in a third-person plural compound-past verb.
- Use s-au whenever the sentence contains two choices.
- Always write the form with au as one word, without a hyphen.
- Use sau only before a noun, never before a clause.
First check the job of the form: sau connects alternatives, while s-au belongs to a verb with the auxiliary au. The other rules confuse the conjunction with the hyphenated verb form.