John, ______, you should eat less meat but more vegetables.

Peter said that he would come over to have dinner with you tonight.—But I think he. I have been alone for an hour.

Where is my pen? —Oh, sorry, I have taken________ by mistake.

Nearly _______of the earth___covered by sea.

I wonder when they ________ for Beijing. I will go to the train station to see them off when they _______.