e Great Wall is , so the Chinese authorities are working on a monitoring and warning system along the wall to preserve it in the future.

Taking charge of such a bigcompany, I’mafraid, is _____ his ability.

Do you like talking with your friends on the telephone or on the QQ— _______. I enjoy chatting face to face.

It is reported that a space station ______ on the moon in years to come.

Is Jim in the office —No, he ________ the dinning hall.