Natural selection tends to eliminate genes that cause inherited diseases , acting most strongly against the most severe diseases ; consequently , hereditary diseases that are ___ would be expected to be very ___ , but , surprisingly , they are not .
A lethal
D perplexing
B unusual
E rare
C widespread
F acute
選AE
翻譯：自然選擇傾向于淘汰那些導(dǎo)致遺傳病的基因，尤其是多數(shù)嚴重的疾病，由此可推，致命的的遺傳病本該很少見，但令人驚訝的是，實際情況并非如此。
perplex 使復(fù)雜化，使困惑
acute 尖銳的，敏感的，劇烈的，急性的，銳角的