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 up
C. taken on
D. taken off
答案：
(答案→)A. taken in
B. taken up
C. taken on
D. taken off
解析：考查词组：A. taken in 吸收，理解，欺骗B. taken up从事，拿起，占据，C. taken on呈现，雇佣D. taken off起飞，句意：这些年轻人对这个世界不是太了解，这就是为什么他们很容易受骗的原因。选A。
