Nowadays, children under 1.4 meters _______________ be free to take buses in some cities. 

—Hi, Johnson, any idea where Susan is?—It's class time, so she       in the classroom now.

— Is there an express to Beijing tonight? — There ______ be, but you’d better call the booking office to make sure. 

—Mum, must I wash the dishes right now?—No, you ____.

 —Look at the boy running on the ground. Is it David?—It      be him. I saw him go to the teacher’s office just now.