问题补充：
These teenagers don’t know much of the world yet; that’s why they are so easily .
A. taken in
B. taken on
C. taken up
D. taken over
答案：
(答案→)A. taken in
B. taken on
C. taken up
D. taken over
解析：考查短语辨析。taken in 欺骗，taken on 呈现，taken up 从事，taken over 接管，句意：这些青少年对世界了解的还不够多；那就是他们如此容易被欺骗的原因。所以选A。
