I LOST MY PEN. I HAVE LOOKED ………..IT ALL DAY. (AT/ AFTER/ UP/ FOR)

2. - DE THI THU DAP AN TS VAO 10 BINH DINH
Lớp 10 Tiếng Anh DE THI THU DAP AN TS VAO 10 BINH DINH
2. I lost my pen. I have looked ………..it all day. (at/ after/ up/ for)