atarasii kyouzai ha kyou no zyugyou de kubararemasita.

A natural way to break it up is:

• 新しい教材は = as for the new teaching materials
• 今日の授業で = in today’s class
• 配られました = were handed out / were distributed

So the grammar pattern is roughly:

[topic] は [time-related noun phrase + setting] で [verb]

In this sentence, the topic is 新しい教材, and the action is 配られました.

Because 新しい is an い-adjective, and in Japanese, an い-adjective goes directly before the noun it modifies.

• 新しい教材 = new teaching materials

This works like:

• 大きい家 = a big house
• 面白い本 = an interesting book

There is no extra word like is between the adjective and the noun.

は marks 新しい教材 as the topic of the sentence.

So the sentence is not just saying that the materials were handed out; it is framing the sentence around the new teaching materials.

• 新しい教材は… = as for the new teaching materials…

If you used が, it would sound more like identifying the subject in a more direct or focused way.
With は, the sentence feels more like neutral topic-comment structure, which is very common.

Also, in passive sentences, the thing affected by the action is often made the topic with は.

今日の授業 means today’s class or the class today.

• 今日 = today
• 授業 = class / lesson
• の links the two nouns

Here, の does not only mean possession in the narrow English sense. It often connects nouns in a broad way.

So:

• 今日の授業 = today’s lesson/class
• 日本語の先生 = Japanese teacher / teacher of Japanese
• 学校の図書館 = the school library

Here, で marks the place, setting, or occasion where the action happened.

So:

• 今日の授業で配られました = it was handed out in / during today’s class

This で is not marking a tool or means here. It is marking the situation in which the distribution took place.

Compare:

• 教室で配られました = it was handed out in the classroom
• 授業で配られました = it was handed out in class / during the lesson

配られました is the polite past passive form of 配る meaning to hand out or to distribute.

• 配る = to hand out
• 配られる = to be handed out
• 配られました = was/were handed out

Japanese often uses the passive when the focus is on the thing receiving the action, rather than on the person doing it.

Here, the sentence focuses on the new materials, not on who handed them out.

An active version would be something like:

• 先生が新しい教材を今日の授業で配りました。
• The teacher handed out the new materials in today’s class.

The passive version sounds natural when the doer is obvious or unimportant.

It is simply omitted.

Japanese very often leaves out information that is clear from context or not important. In a classroom situation, the person handing out materials is probably obvious, such as the teacher.

If you wanted to include the doer in the passive sentence, you could say:

• 新しい教材は今日の授業で先生に配られました。

Here, に marks the agent in the passive sentence:

• 先生に = by the teacher

But in many real situations, leaving it out is more natural.

Because 教材 is not functioning as a direct object here.

In the active sentence:

• 先生が新しい教材を配りました。
• The teacher handed out the new materials.

Here, 教材 is the direct object, so it takes を.

But in the passive sentence:

• 新しい教材は配られました。

Now the materials are the thing being talked about as the topic, so は is used instead of を.

It could be either, depending on context.

Japanese nouns usually do not mark singular vs. plural the way English does. So 教材 can mean:

• teaching material
• teaching materials

In this sentence, English might translate it as the new teaching materials were handed out, but the new handout was handed out could also be possible in the right context.

You have to rely on context rather than noun endings.

It comes from the verb 配る, which is a godan verb.

The steps are:

1. 配る
2. Change る to the passive base られ after the a-row change: 配られる
3. Make it polite past: 配られました

So:

• 配る = hand out
• 配られる = be handed out
• 配られました = was/were handed out

Its reading is くばられました.

Yes, but the nuance is a little different.

• 今日の授業で = in today’s class
• 今日、授業で = today, in class

The original sentence treats today’s class as one unit. It specifically locates the action in that particular class session.

If you say 今日、授業で, you are separating today and in class more clearly. That is also natural, but it is not exactly the same phrasing.

So both can work, but 今日の授業で is a compact way to mean during today’s lesson.