yoru wa tsuuro ga kurai node, ki o tsukete kudasai.

At night, the passageway is dark, so please be careful.

Breakdown of yoru wa tsuuro ga kurai node, ki o tsukete kudasai.

• は: topic particle
• が: subject particle
• 夜よる: night
• ください: please

Questions & Answers about yoru wa tsuuro ga kurai node, ki o tsukete kudasai.

Why is 夜 followed by は instead of に?

In this sentence, 夜は means something like as for nighttime or at night.

A learner might expect 夜に because に often marks time, but Japanese does not always use に with broad or natural time words like:

• 今日 = today
• 明日 = tomorrow
• 夜 = night
• 夏 = summer

Using は here makes 夜 the topic:
As for nighttime, the passage is dark, so please be careful.

So 夜は sets the scene rather than simply marking a time point.

Why does 通路 take が?

が marks the thing being described by the adjective 暗い.

So:

• 通路が暗い = the passage/hallway is dark

This is a very common pattern:

• 空が青い = the sky is blue
• 部屋が広い = the room is spacious
• 道が危ない = the road is dangerous

Here, 夜は is the topic, and within that topic, 通路が暗い is the statement being made.

What is the difference between ので and here?