57.Don't let anyone know about it. Keep it as as_______. 57____________

56.Everyone agreed with his _______ (决定).　　　　56____________

55.Tigers in the world are _______ (消失) now. 　　　55____________

54.The house was c________ destroyed in the big fire.　54____________

53.You're so fat that you should lose some w_______.　 53____________

52.There are seven ________ (工程师) in our factory.　 52____________

51.Ap_______ is a person who is ill.　　　　　 51____________