kono mondai wa jugyou de sensei ni setsumeisareru.

topic particle

Breakdown of kono mondai wa jugyou de sensei ni setsumeisareru.

• 先せん生せい: teacher
• で: location particle
• この: this

Questions & Answers about kono mondai wa jugyou de sensei ni setsumeisareru.

Why is 説明される in the passive, and what is the active version of this sentence?

説明される is the passive form of 説明する (“to explain”).

• 説明する → “to explain”
• 説明される → “to be explained / will be explained”

The sentence is:
この問題は授業で先生に説明される。
Literally: “This problem, in class, by the teacher, will be explained.”

The corresponding active sentence would be:
先生は授業でこの問題を説明する。
“(The) teacher will explain this problem in class.”

Japanese often uses the passive when the focus is on the thing affected (ここでは この問題) rather than on the doer (先生).

Why is the teacher marked with に (先生に) instead of が like in the active sentence?

In a passive sentence in Japanese, the doer of the action (the agent) is usually marked with に.

• Active:

  • 先生がこの問題を説明する。
  • “The teacher explains this problem.”
  • The teacher (doer) → が

• Passive:

  • この問題は先生に説明される。
  • “This problem is explained by the teacher.”
  • The teacher (doer) → に

So 先生に corresponds to English “by the teacher” in a passive construction.

Why is この問題 followed by は and not by が or を?