A-A+
Why can the hummingbird can hover and even fly
问题详情
Why can the hummingbird can hover and even fly backwards？
A．Because its wings are large enough.
B．Because it can tilt its body.
C．Because it has whirling and horizontal blades like a helicopter.
D．Because it can produce down-draft of air by beating their wings very fast此题为多项选择题。请帮忙给出正确答案和分析，谢谢！
参考答案
正确答案：D
解析：本题考查分析判断能力。Hummingbirds have paralleled even this．They tilt their bodies so that they arc almost upright and then beat their wings as fast as 80 times a second producing a similar downdraft of air. So the hummingbird can hover and even fly backwards．此句话解答了问题。
