The room is in a terrible mess; it________have been cleaned

Jack is funny make us happy after class.

The teacher _____ his students to leave the classroom as soon as possible. [ ]

Helen has got ________ it takes to be a great tennis player. In other words, she has the potential to become world famous.

Tony ____ for the company as an engineer for two decadesNow he teachesmechanics m Peking University