Being constantly exposed to advertisements is annoying, but it ______ be pleasant sometimes.

---Someone is knocking at the door. Is it your brother?---No, it        be him. He’s gone to Hunan.

—Will you buy me a new iPod, Dad?—OK. You __________have one if you promise to take care of it. 

— Did you visit the museum today? — No. We ______ it, but we spent too much time shopping.     

It has been announced that students _______ remain in their seats until all the papers have been collected.