18．
Imagine having a ear made out of an apple．It seems like a crazy idea from a horror movie．But it could happen in the near future．
Canadian biophysicist Andrew Polling used an apple to grow a human ear．He think fruit and vegetables can be used to cheaply repair human body parts in the future．
Scientists have been trying to grow organs （器官） in labs to replace our old ones．But it is a hard job．For example，liver cells （肝细胞） can grow in a lab，but he cells still need things like blood vessels （血管） to actually work．These things have to grow inside a scaffold（支架）．
In the past，scientists have used man-made materials，animals parts and even dead people as scaffolds．But that has proved to be difficult and expensive．
Polling and his team，however，found the apple to be a cheap and easy-to-use scaffold．
They first cut an apple into the shape of an ear．Then they used a special way to take out the apple's cell and make it a scaffold．The team then added human cells to the apple，and watched it grow．
"You can implant these scaffolds into the body，and the body will send in cells and a blood supply and actually keep these things alive，"Polling said during a Ted Talk speech．
The team put the apple scaffold inside a living mouse and the mouse's cells slowly took over the pieces of apple．
Now Polling is thinking of other fruit，plants or vegetables to use．
He says that the shape of flower petals could be perfect for repairing skin．And asparagus（芦笋） could fix a broken spine（脊柱）．
Now，Polling and his team are trying hard to put these crazy ideas into reality．
42．Polling's idea of man-made ear seems crazy because he useDas scaffolds．
A．animal parts
B．dead people
C．man-made materials
D．ordinary apples
43．The underlined word"implant"in Paragraph 7 probably meansB．
A．pick
B．put
C．produce
D．protect
44．Which is the right order of making an ear out of an apple according to the passage？C
a．put the apple scaffold inside a mouse
b．add human cells to the apple scaffold
c．cut an apple into the shape of an ear
d．make the apple ear a scaffold
e．take out the apple's cells in a special way
A．a-b-c-d-e B．b-c-d-a-e C．c-e-d-b-a D．c-d-a-e-b
45．From the last three paragraphs，we can infer that Pelling will experiment with other fruit，plants or vegetablesD．
A．to make human ears
B．to repair burnt skin
C．to fix a broken spine
D．to make human body parts．
