烟雾浓度的参数包括（）、质量浓度、减光度、光学密度、减光系数。A、体积浓度 B、摩尔浓

A car drew up outside the Swan Hotel and a young man got out．Pausing only for an instant to see that he had come to the right place，he went into the hotel and rang the bell on the counter of the bar．

Mrs．Crump，the landlady，who was busy in the kitchen at the time，hurried out，wiping her

hands．The young man raised his hat．“Excuse me，”he said．“I’m looking for my uncle，Mr．White．I believe he is staying here．” “He was staying here．”Mrs．Crump corrected him．“But I’m afraid that he went back to London yesterday．” “Oh，dear，”said the young man，looking disappointed．“I understood that he was going to stay here until the end of the month．At least that is what his servant told me when I rang up his house．” “Quite right，”said Mrs，Cramp．“He intended to stay here the whole of July，as he always does． But yesterday he got a telegram to say that his relative was ill．So he caught the train back to London immediately．”  “I wish he had let me know,”The young man said．“I wrote him a letter saying that I was coming．I’ve had all this trouble for nothing．Well，since he isn’t here，there’s no point in waiting．”

He thanked Mrs．Grump and went out．Mrs．Grump went to the window and watched him

drive off．When his car was out of sight，she called out：“You can come out now,Mr．White.He’s gone．”

Mr．White came out of the kitchen，where he had been waiting．

“Many thanks，Mrs．Grump，”he said，laughing，“you did that very well．These nephews of mine never gave me any peace．That young man is the worst of them all．As you see，when he needs money,he even follows me into the country．Well，perhaps next time he won’t warn me by writing a letter!”

49．The young man said “Oh，dear” to express his           ．

    A．disappointment       B．sadness       C．surprise      D．anger

50．This story is about a man         ．

A．who was very much loved by his nephews 

B．whose nephew went to visit him at the hotel

C．whose nephew is always asking him for help

D．who was not willing to meet his nephew

51．When his nephew came to the hotel，Mr．White            ．

A．took the train back to London            B．left to visit a sick relative

C．went to pick up a telegram               D．hid himself in the kitchen

52．Mr．White didn’t like his nephews because         ．

A．they always follow him around            B．they frequently disturb their relatives

C．they won’t write to him often             D．they usually visit him in hotels

奠定了三国鼎立局面的战争是( )。

A．祖逖北伐

B．官渡之战

C．赤壁之战

D．八王之乱

血清铁及血清铁蛋白均增高的疾病是（）

A.维生素C缺乏症

B.消化性溃疡

C.缺铁性贫血

D.再生障碍性贫血

E.恶性肿瘤

在自检过程中的异常情况有（）种处理措施。分别是（）、（）、（）、（）、（）、（）。

什么叫“学堂乐歌”？