Section C?? passage two
51.[C]
Teenagers’ mental problems are often too conspicuous not to be observed.
解析：答案定位在文章第一段， “Teenagers at risk of depression, anxiety and suicide often wear their troubles like a neon（霓虹燈）sign. Their risky behaviors—drinking too much alcohol, using illegal drugs, smoking cigarettes and skipping school—can alert parents and teachers that serious problems are brewing.” 在這個段落中指出，青少年經(jīng)歷在這樣的危險(xiǎn)中：抑郁，焦慮和自殺，且危險(xiǎn)愈來愈烈；這些行為：飲酒過度，吸食毒品，吸煙及逃學(xué)曠課，警示著父母及老師。通過文中的“neon（霓虹燈）sign” 到就可以選出正確選項(xiàng)C：
“青少年的心理問題尤為明顯且讓人易注意到”。

52. [D] Many hitherto unobserved youngsters may have psychological problems.
解析：答案定位在文章第三段的第一句“Of course, that may sound like a description of every teenager on the planet”（似乎地球上的所有年輕人都有這些心理問題），其中“a description of every teenager on the planet”直接對應(yīng)題目中的many hitherto unobserved youngsters，因此就可以選出正確選項(xiàng)D：
“許多之前沒發(fā)現(xiàn)的年輕人都有這些心理問題”。
53. [B] Their behaviors do not constitute a warning signal.
解析：答案定位在文章第三段最后一句“Because their behaviors are not usually seen as a red flag, these young people have been dubbed the“invisible risk”group by the study’s authors”，其中“as a red flag（危險(xiǎn)信號）”直接對應(yīng)題目中的a warning signal（危險(xiǎn)的信號），由此就可以選出正確選項(xiàng)B：
“他們的行為并未構(gòu)成一個危險(xiǎn)的信號”。
54. [A] They are almost as liable to depression as the high-risk group.
解析：答案定位在文章第七段，“The group that scored high on all nine of the risk behaviors was most likely to show symptoms of depression; in all, nearly 15% of this group reported being depressed., compared with just 4% of the low-risk group. But the invisible group wasn’t far behind the high-risk set,with more that 13%of them exhibiting depression.”。通過分析段落中的數(shù)據(jù)不難得出，具有較高危險(xiǎn)行為的學(xué)生群體的數(shù)據(jù)近乎15%，而這些 invisible group的數(shù)據(jù)為13%，由此可以選出正確選項(xiàng)D：
“這些危險(xiǎn)行為不明顯的學(xué)生幾乎與危險(xiǎn)行為明顯的學(xué)生一樣多”。
55. [B] It provides new early-warning signals for identifying teens in trouble.
解析：答案定位在文章最后一段，“Carli says that one of the most significant things about this study is that it provides new early-warning signs for parents, teachers and mental health-care providers.”，選項(xiàng)B“ It provides new early-warning signals for identifying teens in trouble.”直接對應(yīng)文中的it provides new early-warning signs for parents, teachers and mental health-care providers， 由此就可以選出正確選項(xiàng)D：
“可以為鑒別青少年的行為提供新的早起征兆”。
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