their own mother. The other half heard that of another mother, but not
their own.
In both cases, the poem caused a cha nge in the baby's heart rate.
The heart rate accelerated among those who heard their own mother's voice, and decelerated among those who heard a voice other tha n that of their mother's.
Deceleration of the heart rate is
“ an attention mechanism (
Kisilevsky says. The heartbeat among fetuses who heard an un familiar voice slowed dow n, she says, because they were pay ing close atte nti on to a voice they did not recog ni ze. The fact that the heartbeat cha nged in both cases — up for Mom, dow n for some one else — shows the fetuses
“ noticed both voices she,says, and could tell one from the other.
By the way, the poem is immaterial
here. Kisilevsky suspects she
would have had the same results if the mothers had been reading a phone book. “It's not the content that the fetuses recog ni zed says. “ We all have our own way of talking. We stop at diff erent times, take breaths at differe nt times, and that's what they are recog nizing.
语篇解读：本文是一篇说明文，主要介绍了一项有关胎儿对声音的识别的 研究。 12 . What did Kisilevsky's research find? A. Babies are good Ianguage learners.
B. Babies' la nguage acquisiti on beg ins after birth.
机制
C．Babies can recognize Mom's voice while in the womb. D．Infants are more sensitive to Mom's voice than fetuses. 解析：选 C 细节理解题。根据第一段中的“
Even before we were born,
we knew our mother's voice and could distinguish it from other voices 并结合下文内容可知，我们在出生之前就已经熟悉母亲的声音，并能将其与其 他声音区分开来。 由此可知，婴儿在母亲的子宫中就能识别母亲的声音。 故选 C。
13 ．What led to the change in fetuses' heart rate according to the research?
A．Their familiarity with the voice. B．The quality of the recordings. C．Their curiosity about everything. D．The content of the poem recorded.
解析：选 A 细节理解题。根据倒数第二段中的第二句可知，在研究中， 胎儿对声音的熟悉度的不同导致了他们心率的变化。故选 A 。
14 ．What can be inferred from the last paragraph?
A．Adults talk in a way quite different from babies. B．Kisilevsky firmly believes her findings are applicable. C．Speech patterns are what fetuses recognize in telling voices. D．Different experimental materials can lead to different results. 解析：选 C 推理判断题。根据最后一段的内容，尤其是最后一句可知，
胎儿在辨别声音时识别的是人们的说话方式，即他们的语言模式。故选C。
