The Last Leaf is a short story written by US author O． Henry． One of the most famous short story writers in history． His stories are known for their surprising endings， now called "O． Henry endings"．

In the story of The Last Leaf， Sue and Joanna are two artists living in New York City． Unfortunately， Joanna is ill and will probably die． In the hospital， something touching and unexpected happens． Let's find out more in the following excerpt（节选）．

Sue looked out of the window． All she saw was an old yellow and green ivy（常青藤） plant． The half﹣dead plant had few leaves on it because of the autumn winds．

"There are only five， now，" said Joanna．

"Five what， dear？ What are you counting？"

"The ivy leaves，" replied Joanna． "When the last one goes， I'll die． I've known that for two days． Didn't the doctor tell you about it？"

"Joanna， don't say that． Now， eat some soup and I'll finish my picture．"

"I don't want any soup，" said Joanna， looking out of the window． "Now there are only four．"

"Joanna dear， try to sleep． I must ask Mr． Berman to come up． I want to draw a picture of him as a poor old farmer．"

Mr． Berman， who was over 60years old， lived downstairs． He was a painter， too， but he never sold anything， and he drank a lot． Sue told him all about what Joanna was saying．

"She can't really think that this will happen! The poor woman!" he said．

…

Finally there was only one last leaf on the ivy plant． After a few windy days， the leaf was still there．

"Susie，" said Joanna， "I've been a bad girl． That last leaf is telling me that it was very wrong of me to want to die． Bring me some soup， dear．"

The next day， the doctor said： "She's out of danger． But poor Mr． Berman downstairs is dying． There's no hope for him， I'm afraid．"

That afternoon Sue went into Joanna's bedroom．

"Joanna dear， Mr． Berman died today． And do you know why？ One terrible， cold wet night he took a ladder and some green and yellow paint and he climbed up， and ﹣ oh， look at the last ivy leaf on the wall! Why didn't it ever move in the wind？ Can't you see？ It was Mr． Berman's last great picture． He painted it there the night that the last leaf fell．"

48． In this sentence "She can't really think that this will happen!"， "this" refers to　　．

A： Joanna didn't eat any soup

B： The doctor said she would die

C： Joanna counted the leaves of the ivy plant

D： Joanna thought when the last ivy leaf went， she would die

49． Why didn't the last ivy leaf fall after a few windy days？　　

A： Because it was painted on the wall．

B： Because the leaf was green．

C： Because the wind wasn't strong．

D： Because it was tied to the tree．

50． Why did Mr． Berman paint an ivy leaf on that wall on a terrible， cold wet night？　__　

A： Because Susie asked him to do so．

B： Because he drank a lot and nobody could stop him．

C： Because he liked the ivy plant and wanted to paint it before he died．

D： Because that night the last ivy leaf fell， he didn't want Joanna to lose hope．

51． From the passage we know that　　．

A： Joanna was a bad girl without hope in her life

B： Mr． Berman was a very kind， great artist

C： Susie never let Mr． Berman know what Joanna said．

D： Mr． Berman's pictures were so terrible that he couldn't sell them out．