課題を

assignment

→ 課題
phrase Uncommon #18,768
assignment 課題 means an assignment, task, or challenge; を marks it as the direct object of the verb that follows. In school contexts, it commonly means homework or an assignment.
JA: 今日の課題を終わらせました。
EN: I finished the assignment before dinner.

一緒に課題をやるんだ

We're going to work on the assignment together.

— Hoje Eu Quero Voltar Sozinho (2014)

うちで課題をする

I do my homework at home.

— Hoje Eu Quero Voltar Sozinho (2014)

彼はその難しい課題をがんばってやった

He worked hard on that difficult assignment.

昨日課題をやった?

Did you do your homework yesterday?

— Hoje Eu Quero Voltar Sozinho (2014)

課題をする気分じゃない

I don't feel like doing my homework.

— Hoje Eu Quero Voltar Sozinho (2014)

美術課題を放課後に手伝ってあげた

I helped them with their art assignment after school.

— ダーク・プレイス (2015)

次の課題をより難しくします

I'll make the next assignment more challenging.

— バーフバリ 伝説誕生 (2015)

ラリッサ課題をやるんじゃ?

Aren’t you going to do the assignment with Larissa?

— Hoje Eu Quero Voltar Sozinho (2014)