窓は開けた

opened the window

→ 窓
phrase Rare #36,814
opened the window 窓は means “as for the window,” and 開けた is the past form of 開ける, “to open.” In related expressions, 窓は開けたままで means “leave the window open,” and 窓は開けた方がいい means “should open the window.”
JA: 窓は開けたから、部屋は涼しいよ。
EN: I opened the window, so the room is cool.

窓は開けた方がいい

Should I open the window?

窓は開けたままでお願いします

Please leave the window open.

二階窓は開けた

I opened the second-floor window.