The object marker אֶת

A direct object that is definite takes אֶת et before it. English has no word like it, but Hebrew needs it. Definite means: a noun with ה, a name, a joined noun whose second noun has ה, זֶה or זֹאת, and כָּל before a noun with ה.

• רָאִיתִי אֶת הַסֶּרֶט.
  ra'iti et haseret
  I saw the film.
• אֲנִי מַכִּיר אֶת יוֹסִי.
  ani makir et yosi
  I know Yossi.
  a man speaking
• מָצָאתִי אֶת בֵּית הַסֵּפֶר.
  matsati et beit hasefer
  I found the school.
• אֲנִי רוֹצָה אֶת זֶה.
  ani rotsa et ze
  I want this.
  a woman speaking
• אָכַלְתִּי אֶת כָּל הָעוּגָה.
  akhalti et kol ha'uga
  I ate the whole cake.

An indefinite object takes no אֶת: רָאִיתִי סֶרֶט "I saw a film". Only direct objects take it, never the subject or a noun after a preposition.

With pronouns

With a pronoun, אֶת takes an ending: אוֹתִי oti "me", אוֹתְךָ otkha and אוֹתָךְ otakh "you", אוֹתוֹ oto "him, it", אוֹתָהּ ota "her, it", אוֹתָנוּ otanu "us", אֶתְכֶם etkhem "you" to a group, אוֹתָם otam "them". The whole table is in Prepositions with endings.

• אַתָּה זוֹכֵר אוֹתָהּ?
  ata zokher ota?
  Do you remember her?
  to a man
• קָנִיתִי אֶת הַסְּפָרִים וְקָרָאתִי אוֹתָם.
  kaniti et hasfarim vekarati otam
  I bought the books and read them.

In questions

"Whom" is אֶת מִי et mi. מָה "what" usually goes without אֶת.

• אֶת מִי רָאִיתָ?
  et mi ra'ita?
  Who did you see?
  to a man
• מָה קָנִית?
  ma kanit?
  What did you buy?
  to a woman