The main work is as follows: Firstly, embarking from the structure of insect and bird wing, this paper analyzed the flight mode, the flight theory and the flapping-wing motion pattern of two kind of flights biology.

And the trailing edge has a flexible fringe, unlike the rigid trailing edge of a conventional bird wing.

而接下去的尾端则是一小段柔韧的弯曲，不像是一般的羽翼末端那样坚硬。

To the ancient Mayans of CentralAmerica the bird was Moan, a bird of ill omen and death.

对中美洲的古代玛雅人来说，热带大雕就是Moan，一种带来不祥和死亡的鸟。

Douglas told us that he had witnessed another motorway crash; he seems to be a bird of ill omen.

道格拉斯告诉我，他又目睹了一桩快车道撞车事件；他似乎总是报凶讯。

Although I was not a bird watcher, my first glimpse of the adorable puffin won me over.

尽管我不是一名观察研究野鸟的学者，但是当我第一眼看到那可爱的海鹦，就被它迷住了。

Teddy: well you know he's a keen bird watcher do not you?

泰迪：他热中观察野鸟，这是你知道的吧？

The bird watcher has been looking for the first robin to appear in the spring.

这位鸟类观察者一直在寻找出现在春天里的第一只知更鸟。

Rachel Carson was a scientist and a bird watcher.

拉琪尔•卡森是一位科学家兼鸟类观察家。

Relationship between Total Phenol in White Birch Wood and Wood Rot Fungi

白桦木材中总酚含量与抗木材腐朽菌的关系

Regularity of Juice Flowed from Asian White Birch and Its Composition Analysis

桦树汁液的外溢规律及其成分分析

Artificial regeneration techniques for Korean Pine under white birch forest

白桦林下红松人工更新技术的研究

A study on the drying properties of white birch before and after urea modification

白桦材尿素改性前后干燥特性的研究

The Preliminary Study on Drying Process Traverse Strains of Asian White Birch

白桦木材干燥过程横纹流变特性的初步研究

Optimization of Manufacturing Technology for Particleboard Made by White Birch Branch Material

白桦枝桠材制造刨花板的优化工艺

In Beijing, for example, the most common allergenic pollens in spring include those from the large-fruited elm tree, Cathay poplar, ash, acacia and white birch.

以北京为例，春季最常见的致敏花粉包括榆树、杨树、白蜡、合欢树和白桦的花粉。

Partial Substitution of Hybrid Larch and Birch for Black Spruce TMP for the Production of Newsprint Grade

用落叶松和白桦代替部分黑云杉生产新闻纸用TMP

And the black dragon hill forest birch in young and middle aged forest harvesting and forest stand growth and structure were analyzed, mainly including: the average diameter of stand diameter structure, accumulation, spatial structure, etc..

并对黑龙山林场白桦中幼龄林采伐前后林分生长和结构差异进行分析，主要包括：林分平均直径、蓄积、直径结构、空间结构等。

The two differ, Luan of the first month forest farm forest more class, while the black dragon hill forest birch sapling forest maximum diameter is 9, and the tree numbers less.

两地不同之处在于，孟滦林场大阶级林木较多，而黑龙山林场白桦幼龄林最大径阶为9，且林木株数较少。

Black dragon hill forest birch sapling forest aggregation degree than Luan of the first month forest birch sapling forest aggregation degree is bigger.

黑龙山林场白桦幼龄林聚集程度比孟滦林场白桦幼龄林聚集程度较大。

The significant edge effect was found in Korean pine, white birch, black birch and aspen stands.

边缘效应表现显著的树种有红松、白桦、山杨和黑桦。

In all factors of vegetation structure characteristic, the average height of shrubs, the average canopy of trees and the average canopy of grass are difference factors in whole level, and the density of Black birch ( Betula dnvurica) is difference factor in specific composition level.

各样地的植被结构特征因子中，灌木平均高度、乔木平均盖度（郁蔽度）、草本平均盖度是各样地在总体水平上的差异因子，黑桦密度是样地树种组成水平上的差异因子；