If people eat natural poisons by mistake, they ________ go to hospital without delay.

Teenagers _______ allowed to drive in the street．

 ______ Tom be in his office so late at night ?

— I think Mr. Zhang may be in his office.— No, he _____ be there. I saw him ____ there just now.

— My sons are not a little restless.— Oh? Boys _______ be boys．