[請益] TOP閱讀 Biological clocks插句題

看板TOEFL_iBT (TOEFL_iBT托福)作者FenderST54 (Fender)時間15年前 (2011/05/27 15:51)推噓0(0推 0噓 0→)

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答案為B 但我覺得B選起來有點突兀我的想法是 A不能選因為後面有such an D不能選 drift明顯是連句 C看起來可以因為後面接著提到external相關至於為什麼答案要B我就不知道了懇請解答謝謝! Paragraph 3：Animals need natural periodic signals like sunrise to maintain a cycle whose period is precisely 24 hours. ■Such an external cue not only coordinates an animal's daily rhythms with particular features of the local solar day but also—because it normally does so day after day-seems to keep the internal clock's period close to that of Earth's rotation. ■Yet despite this synchronization of the period of the internal cycle, the animal's timer itself continues to have its own genetically built-in period close to, but different from, 24 hours. ■Without the external cue, the difference accumulates and so the internally regulated activities of the biological day drift continuously, like the tides, in relation to the solar day. ■This drift has been studied extensively in many animals and in biological activities ranging from the hatching of fruit fly eggs to wheel running by squirrels. Light has a predominating influence in setting the clock. Even a fifteen-minute burst of light in otherwise sustained darkness can reset an animal's circadian rhythm. Normally, internal rhythms are kept in step by regular environmental cycles. For instance, if a homing pigeon is to navigate with its Sun compass, its clock must be properly set by cues provided by the daylight/darkness cycle. 13. Look at the four squares [■] that indicate where the following sentence could be added to the passage. Because the internal signals that regulate waking and going to sleep tend to align themselves with these external cues, the external clock appears to dominate the internal clock. Where would the sentence best fit? -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 61.228.43.22