Passage 1
21 sensory
The human brain is a remarkably complex organic computer, taking in
experiences, processing and storing this information, and recalling and integrating selected bits at
22 by Alzheimer's disease has been likened to the erasure
the right moments. The destruction
of a hard drive, beginning with the most recent files and working backward. As the illness
23 new memories gradually disappear until even loved ones are no longer
progresses, old
24
recognized. Unfortunately, the computer analogy
; one cannot simply reboot the human
brain and reload the files and programs. The problem is that Alzheimer's disease does not only erase
more than 100 billion
information; it destroys the very hardware of the brain, which
nerve cells (neurons), with 100 trillion connections among them.
21. (A) a scanty touch with (B) a wide variety of (C) face-to-face
(C) that caused
B
22. (A) was caused
(B) causing
25
(D) a full volume of
(D) caused
