Hummingbirds are small, often brightly colored birds of the family Trochilidae that live exclusively in the Americas. About 12 species are found in North America, but only the ruby-throated hummingbird breeds in eastern North America and is found from Nova Scotia to Florida. The greatest variety and number of species are found in South America. Another hummingbird species is found from southeastern Alaska to northern California.
Many hummingbirds are minute. But even the giant hummingbird found in western South America, which is the largest known hummingbird, is only about 8 inches long and weighs about two-thirds of an ounce. The smallest species, the bee hummingbird of Cuba and the Isle of Pines, measures slightly more than 5.5 centimeters and weighs about two grams.
Hummingbirds' bodies are compact, with strong muscles. They have wings shaped like blades. Unlike the wings of other birds, hummingbird wings connect to the body only at the shoulder joint, which allows them to fly not only forward but also straight up and down, sideways, and backward. Because of their unusual wings hummingbirds can also hover in front of flowers so they can suck nectar and find insects. The humming- bird's bill, adapted for securing nectar from certain types of flowers, is usually rather long and always slender, and it is curved slightly downward in many species.
The hummingbird’s body feathers are sparse and more like scales than feathers. The unique character of the feathers produces brilliant and iridescent colors, resulting from the refraction of light by the feathers. Pigmentation of other feathers also contributes to the unique color and look. Male and female hummingbirds look alike in some species but different in most species; males of most species are extremely colorful.
The rate at which a hummingbird beats its wings does not vary, regardless of whether it is flying forward, flying in another direction, or merely hovering. But the rate does vary with the size of the bird - the larger the bird, the lower the rate, ranging from 80 beats per second for the smallest species to 10 times per second for larger species. Researchers have not yet been able to record the speed of the wings of the bee humming-bird but imagine that they beat even faster. Most hummingbirds, especially the smaller species, emit scratchy, twittering, or squeaky sounds. The wings, and sometimes the tail feathers, often produce humming, hissing, or popping sounds, which apparently function much as do the songs of other birds.
What does the author imply about the rate hummingbirds’ wings beat?
Suy nghĩ trả lời câu hỏi trước khi xem đáp án
Lời giải:
Báo saiĐáp án D
Theo thông tin xuất hiện ở cuối đoạn 5 “Researchers have not yet been able to record the speed of the wings of the bee humming-bird but imagine that they beat even faster.” (Các nhà nghiên cứu vẫn chưa thể ghi lại tốc độ đập cánh của loài chim ruồi ong nhưng hãy tưởng tượng là chúng đập thậm chí còn nhanh hơn.), ta có suy ra rằng tốc độ đập cánh của chim ruồi ong vẫn chưa được biết rõ.
1400 câu trắc nghiệm Đọc hiểu Tiếng Anh có đáp án cực hay
Tổng hợp 1400 câu trắc nghiệm Đọc hiểu Tiếng Anh có đáp án cực hay có đáp án nhằm giúp học sinh ôn tập tốt dạng bài đọc hiểu cho kì thi THPT QG .