Marking the subject with が

が marks the subject: who acts or what exists. 猫ねこ が います means “There is a cat,” and けんさん が 来きます means “Ken is coming.” The noun before が tells you who or what the statement is about grammatically.

English often signals the subject through its position before the verb. Japanese uses particles to make roles clear, and its verbs do not change for “I,” “you,” or “they.” が helps identify the subject when it needs to be stated.

Use が with “who?” when asking someone’s identity or role: 「誰だれ が 先生せんせい です か。」→「けんさん が 先生せんせい です。」 Here the answer identifies Ken as the teacher. That identifying emphasis comes from the question and context; が does not always mean “and nobody else.”