大全-Ⅲ-19 9.6 不明白

大全-Ⅲ-19.  Identical twins tend to have
similar personalities; if environment outweighs heredity in personality
development, twins raised together should presumably have more similar
personalities than those raised apart. A recent study of identical twins in
both situations measured 11 key traits through a questionnaire, and concluded
that 7 of the 11 are primarily products of heredity.

Which of the following, if established,
would cast the most doubt on the study’s results?

(A) Fewer than
half of the pairs of twins studied were raised separately.

(B) The ages of
all of the twins studied fell within a 10-year range.

(C) Some of the traits that the
study attributed to heredity developed in the separately raised twins because
those pairs all grew up in similar families.

(D) Although over half the
traits measured were determined to be linked to heredity, the nature of those
traits varied widely.（C）

(E) The 11
traits that were measured constitute a representative sample of larger,
generally accepted pool of key personality traits.

削弱题？呵呵

D是无关选项 ，注意 the nature of those traits不是同一个trait 的不同表现形式，而是不同的trait，所以是无关的。

而C有效的说明了 并不是因为 identical twins have similar personalities，而是 similar families

我的意见稍微有奌不同。我认为C并没有否认identical twins have similar personalities，只是说某些性格的相似是因为后天的环境相似（similar families）而不是基因(heredity)引起的，但这些相似性被错误地归功于heredity，所以削弱了研究结果。