ASK STS TO ADDWHO , WHOEVER ,WHOM , WHOSE , WHICHKEYS

3.Which: chỉ vật có thể làm chủ ngữ hoặc tân ngữ.

Vd: Her hat is yellow. It is on the table.

Her hat which is on the table is yellow.

Vd: Her hat is yellow. I see it on the table.

Her hat which I see on the table is yellow.