Don’t forget ____________ the lights when you leave.
Put on your coat, Jack! It's snowing _______ outside at the moment.
—Is that Tom in the teachers' office?--No, it ________ be him. He's gone to the hospital.
Last night, Dan hung out with his friends too late. When he came home, he went upstairs without a _______. But to his surprise, his father was sitting in his room.
---Why didn't you go to the party last night?---Because I was waiting for Sam in his office _______ he came back.
—Hey! Peter! What are you looking at?---I find ________ hole in the blackboard, let's go and tell Mr. Wang about it.