动作动词祈使句 — 英语情景题

情景对话：课间操时间到了，体育委员 Lily 在操场上给同学们发指令。请从方框中选择合适的句子补全对话（每句限用一次）。 A. Stand up, please. B. Sit down, please. C. Open the door, please. Lily: Good morning, Sam! It's time for exercise (做操时间到了). (1)________ Sam: OK. I'm standing now. Lily: Now let's go out. Tom, (2)________ Tom: All right. I'll open it. Lily: Exercise is over. (3)________ Sam & Tom: Thank you, Lily!