问题补充:
Teenagers should learn to protect (保护) from all kinds of dangers.
A. them
B. they
C. their
D. themselves
答案:
A. them
B. they
C. their
(答案→)D. themselves
解析:句意:青少年应该学会保护自己避免各种危险。A他们,宾格,用在动词或介词后作宾语,B他们,主格,作主语,C他们的,形容词性物主代词,修饰名词,D他们自己,反身代词,只能做宾语和同位语。指动作作用在自己身上。结合句意及结构故选D。