I talked for a long time, and in the end I_____ make her believe me. 

－ Look! Mrs Green is wearing a black dress today.－ I think she _______ wear red. She looks young in red.

--Whose tennis racket is this, Linda?--Look! Jerry's name is on it! It _________ be his.

--Honey, stay home before I return. ---I _______, mum. 

—Look! The man at the gate ______ be our headmaster. He is always standing there every morning.—No, it ______be him. He is holding a meeting in the office now.