求出10到500之内能同时被3、7整除的数，并输出；然后求出其和值。

— We are too busy to take ________ holiday at ________ present.

　　　　— But I think we’ll be able to take ________ two weeks from now.

　　A. a; /; one　　　　　　　　　　　 B. the; /; that

　　C. a; the; it　　　　　　　　　　　 D a; /; it