ESCRIBE EN EL ESPACIO EN BLANCO LA FORMA CORRECTA DEL VERBO TO BE.

1 ) THOSE BOXES ________________ FOUND BY DAVE YESTERDAY.
2 ) ALL THE EXERCISE _____________ BEING DONE BY THE ATHLETES NOW.
3 ) THAT LETTER HAS _____________ SENT BY HER BOYFRIEND.
4 ) THE LECTURE WILL ____________ PREPARED BY THE EXPERT .