LISTEN! SOMEONE ______ AT THE DOOR.A. WILL BE KNOCKING B. IS KNOCK...

24. - 33 DE TRAC NGHIEM CUA MAI LAN HUONG
33 DE TRAC NGHIEM CUA MAI LAN HUONG

24. Listen! Someone ______ at the door.

a. will be knocking b. is knocking c. had been knocking d. will be knocking