51 be made of 由……制成(制成以后还看得见原材料)

　　52 be not sure 表不确定

　　53 be on a visit to 参观

　　54 be popular with sb 受某人欢迎

　　55 be quiet 安静

　　56 be short for 表**的缩写 eg:  is short for

　　57 be sick in bed 生病在床

　　58 be sorry to do sth be sorry for sb eg : I am sorry for you

　　59 be sorry to hear that

　　60 be sorry to trouble sb eg : I am sorry to trouble you