听力原文:M: The city council has finally voted the funds to build a new high school. W: It's about time they did it. I don't know what took them so long. What's the woman's opinion about the school?
【简答题】下列对诗歌的鉴赏,不恰当的一项是( D )A. 诗人把自己对母校的深情融进了悄然别离时那富于特色的形象和想象中。 B. 徐志摩年轻时曾在康桥读书生活过,对康桥怀有一种特殊的感情。 C. 诗歌中水草、柔波、彩虹、星辉等意象,恰当地衬托了诗人静默、悠然的心境。 D. 诗人运用比喻、拟人、借代等修辞手法,写出了康桥那特有的优美景色。 一语未完,只听后院中有笑语声,说:“我来迟了,没得迎接远客!”黛玉思忖...
【多选题】How do point mutations in regulatory DNA sequences change our ability to digest lactose in milk?
A.
Our earliest ancestors were lactose intolerant, because the enzyme that breaks down lactose—called lactase—was made only during infancy. Adults, who were no longer exposed to breast milk, did not need the enzyme.
B.
When humans began to get milk from domesticated cattle some 10,000 years ago, variant genes—the product of random mutation—enabled those who carried the variation to continue to express lactase as adults, and thus take advantage of nutrition provided by cow’s milk.
C.
We now know that people who retain the ability to digest milk as adults contain a point mutation in the regulatory DNA sequence of the lactase gene, allowing it to be efficiently transcribed throughout life. In a sense, these milk-drinking adults are “mutants” with respect to their ancestors
D.
It is remarkable how quickly this adaptation spread through the human population, especially in societies that depended heavily on milk for nutrition. These evolutionary changes in the regulatory DNA sequence of the lactase gene occurred relatively recently (10,000 years ago), well after humans became a distinct species.
同一个图样中每一个表面只标注一次表面粗糙度,在右边和上面可以直接标注,在下面和左边标注时需要用指引线引出标注,粗糙度值的书写应与尺寸数字的书写一至。 K. 同一个图样中每一个表面只标注一次表面粗糙度,在左边和上面可以直接标注,在下面和右边标注时需也可以直接标注,粗糙度值的书写应与尺寸数字的书写一至。 L. 同一个图样中每一个表面只标注一次表面粗糙度,在左边和上面可以直接标注,在下面和右边标注时需要用指引线引出标注,粗糙度值的书写应与尺寸数字的书写一至。符号的尖端应从材料内指向被标注的表面。