2021年托福阅读PASSAGE 62
试题及答案
PASSAGE 62
Molting is one of the most involved process of a bird's annual life cycle. Notwithstanding preening and constant care, the marvelously intricate structure of a bird's feather inevitably wears out. All adult birds molt their feathers at least once a year, and upon clo obrvation, one can recognize the frayed, ragged appearance of feathers that are nearing the end of their uful life. Two distinct process are involved in molting. The first step is when the old, worn feather is dropped, or shed. The cond is when a new feather grows in its place. When each feather has been shed and replaced, then the molt can be said to be complete. This, however, is an abstraction that often does not happen: incomplete, overlapping, and arrested molts are quite common.
Molt requires that a bird find and process enough protein to rebuild approximately one-third
of its body weight. It is not surprising that a bird in heavy molt often ems listless and unwell. But far from being random, molt is controlled by strong evolutionary forces that have established an optimal time and duration. Generally, molt occurs at the time of least stress on the bird. Many songbirds, for instance, molt in late summer, when the hard work of breeding is done but the weather is still warm
and food still plentiful. This is why the woods in late summer often em so quiet, when compared with the exuberant chorus of spring.
描写秋天的好句子Molt of the flight feathers is the most highly organized part of the process. Some species, for example, begin by dropping the outermost primary feathers on each side (to retain balance in the air) and wait until the replacement feathers are about one-third grown before shedding the next outermost, and so on. Others always start with the innermost primary feathers and work outward. Yet other species begin in the middle and work outward on both sides. Most ducks shed their wing feathers at once, and remain flightless for two or three weeks while the replacement feathers grow.
树真好教案
人为什么会害怕
1. The passage mainly discuss how
(A) birds prepare for breeding红尘有泪
床铃(B) bird feathers differ from species
(C) birds shed and replace their feathers
(D) birds are affected by asonal changes
2. The word "Notwithstanding" in line 2 is clost in meaning to
(A) despite
(B) becau of
(C) instead of
护照申请(D) regarding
3. The word "intricate" in line 2 is clost in meaning to
(A) regular
(B) complex
(C) interesting
(D) important
4. The word "random" in line 12 is clost in meaning to
(A) unfortunate
(B) unusual
(C) unobrvable
(D) unpredictable
5. The word "optimal" in line 13 is clost in meaning to
(A) slow
粉刷匠歌词
(B) frequent
(C) best
(D) early
6. Which of the following is NOT mentioned as a reason that songbirds molt in the late summer?
(A) Fewer predators are in the woods.
(B) The weathers are still warm.
(C) The songbirds have finished breeding.
(D) Food is still available.
