单选题 Giorgio, now fifteen, and Lucia, also in her teens, were reaching the ______ of their adolescence.

【正确答案】 A
【答案解析】[解析] 本题空格处是说到了他们的青春转折期。A项crisis“决定性时刻，危机”符合题意。其他三项criterion“(批评判断的)标准，准据，规范”；causality“因果关系”；credibility“可信性”都不正确。