单选题 Sam walked in, with the rest of the boys ____ closely behind.

单选题 I am really ____ about the prospect of working abroad.

单选题 We can not find our car. Could you help ____ find it?

单选题 - ____ students are there in your class? - Forty-nine.

单选题 I did not go the cinema last night. ____ I had to finish my homework.

单选题 - Must I return the dictionary today? - No, you ____. you can return it tomorrow.

单选题 - What is your brother doing now? - He ____ in his room.

单选题 It is ____ useful gadget. I bought it last week.