sono shimai wa shuumatsu ni kouen de issho ni sanposhimasu

Those sisters take a walk together in the park on the weekend.

Breakdown of sono shimai wa shuumatsu ni kouen de issho ni sanposhimasu

• は: topic particle
• で: location particle
• に: time particle
• 一緒いっしょ に: together

Questions & Answers about sono shimai wa shuumatsu ni kouen de issho ni sanposhimasu

Why does the sentence use は after 姉妹?

は marks その姉妹 as the topic of the sentence.

So その姉妹は means something like as for those sisters...

It does not directly mark the grammatical subject in the same way English does. Instead, it tells the listener what the sentence is about.

In this sentence:

• その姉妹は = as for those sisters
• the rest of the sentence tells what they do

A learner may expect が, but は is very common when introducing or talking about a known topic.

What exactly does その mean here?

その means that and is used before a noun.

So:

• その姉妹 = those sisters / that pair of sisters

It usually refers to something already known in the conversation or something closer to the listener than to the speaker.

Compare:

• この姉妹 = these sisters
• その姉妹 = those sisters
• あの姉妹 = those sisters over there / those sisters we both know

Does 姉妹 mean one sister or more than one?