The part of a sentence "the teacher assigned" is correct and usable in written English.
You can use it when you want to talk about something a teacher has given to a student, class, or group to do. For example: "The teacher assigned the class a research project on the history of the Civil War."
The teacher assigned the students to read Barbara Ehrenreich's "Nickel and Dimed: On (Not) Getting by in America".
Although the books that the teacher assigned were set in crazy places, she made connections with ease, and the lesson of the failed Manual protest seemed similar to something that she'd recently written in an essay on "Things Fall Apart," by the Nigerian novelist Chinua Achebe: "Getting beat down help in the future because it breaks you to do whats right instead of fallowing the crowd".
For example, in the topic of plants, the teacher assigned a task for observing the beans' growth.
The teacher assigned a writing topic to the students and asked them to write about it and put their ideas into written words.
The teacher assigned a tally of these scores to each participant at the end of each class, rather than during each class, to minimise disruption to classroom activities.
Besides the normal in-class practice, the teacher assigned them extra home listening materials by uploading them online, together with the necessary answers to questions.
When the teacher assigns a homework assignment that you don't understand, ask the teacher for help.
Write down your homework as soon as the teacher assigns it.
Once a week for six weeks, the teachers assigned tasks that had a specific type of homework purpose according to their treatment condition.
The teachers assigned scores for participation holistically over the semester for both participation and control groups, according to the 10 criteria previously listed in Table 1.
Contact the special needs coordinator for access, or arrange to review the file with the Special Education teacher assigned to that student.
