ヘレンは庭で遊んでいます。

topic marker particle; indicates contrast with another option (stated or unstated); adds emphasis

garden; yard; courtyard; field (of action); area

indicates location of action; at; in; indicates time of action; indicates means of action; cause of effect; by; and then; so; indicates continuing action; indicates certainty, emphasis, etc.

to play; to enjoy oneself; to have a good time; to mess about (with alcohol, gambling, philandery, etc.); to be idle; to do nothing; to be unused; to go to (for pleasure or for study); to intentionally throw a ball to lower the batter's concentration