Read the sentence, looking for clues
The semicolon serves as a straight-ahead roadsign, indicating that the second
clause clarifies (rather than contrasts with) the first clause. Therefore, like
"self-possessed," the missing word would describe someone who demonstrated
composure.
Predict an answer
The correct answers will mean something like "poised," "self-assured," "calm," or
"collected." All of these, as well as others, would be consistent with
self-possession and composure.
Select the two choices that most closely match your
prediction
(B)
reserved, meaning "restrained in words
and actions," and (D)
decorous, meaning "proper, tasteful,"
are consistent with self-possession and composure. Although these words may veer
more toward the topic of etiquette than was expected, no other two choices are
consistent with the prediction, so these two are correct.
(A) nonplussed means "bewildered" and
(C) contrite means "remorseful." Neither
is supported by the context, so both are incorrect.
(E) lethargic and (F) apathetic indicate a lack of excitement (as
suggested in the second clause), but are incorrect because they introduce new
qualities of indifference and boredom that distort the positive description of
"contentment."
Check your answers to see if the sentence retains the
same meaning
The girl's composure was astounding given her youthfulness; reserved/decorous and self-possessed, she
clearly had no predilection for confusing exhilaration with contentment.
TAKEAWAY: Even if you can't find a close match for your prediction, look for a set
of words that are at least consistent with your prediction, that fit the meaning of
the sentence as a whole, and that yield complete sentences that are similar in
meaning.
