What it means
が marks the subject of a sentence or clause. It identifies the person, animal, thing, or event that performs an action or has a state. It is especially common when introducing new information, answering a question about who or what, or describing what exists or happens. The subject marked by が is often different from the topic marked by は.
Usage note
が can also connect clauses with a meaning similar to “but,” so its meaning depends on what follows it. Do not confuse the subject-marking use with this clause-linking use.
How to use it
弟が公園で遊びます。
The younger brother plays in the park.
弟が公園で遊ぶ。
The younger brother plays in the park.
Example sentences
公園で犬が走っています。
A dog is running in the park.
窓の外で鳥が鳴いています。
A bird is singing outside the window.
教室に新しい机があります。
There is a new desk in the classroom.
駅の前に大きな時計があります。