练习材料：
[Day 1758 2019-07-20]
Lesson 23-2 Bird flight
Duck, and like them the pigeons, are endowed with steel-like muscles, that are a
good part of the weight of the bird, and these will ply the short wings with such
irresistible power that they can bore for long distances through an opposing gale before
exhaustion follows. Their humbler followers, such as partridges, have a like power of
strong propulsion, but soon tire. You may pick them up in utter exhaustion, if wind over
the sea has driven them to a long journey. The swallow shares the virtues of both
schools in highest measure. It tires not, nor does it boast of its power; but belongs to
the air, travelling it may be six thousand miles to and from its northern nesting home,
feeding its flown young as it flies, and slipping through a medium that seems to help its
passage even when the wind is adverse .such birds do us good ,though we no longer
take omens from their flight on this side and that; and even the most superstitious
villagers no longer take off their hats to the magpie and wish it good-morning.
任务配置：L0+L1+L4
知识笔记：
endowed v. (向学校等机构) 捐钱，捐赠，资助;
ply v. 定时往来; 定期行驶; (娴熟地) 使用; n. (毛线、绳子、木板等的计量单位) 股，层，厚;
gale n. 大风; 飓风; 一阵(阵)大笑声;
humbler adj. 谦逊的; 虚心的; 表示谦逊，但不够诚挚或认真; (级别或地位) 低下的，卑微的;
partridges n. 山鹑; 山鹑肉;
propulsion n. 推动力; 推进;
in utter exhaustion 筋疲力尽
in highest measure 网络 最大程度地;
adverse adj. 不利的; 有害的; 反面的;
omens n. 预兆; 前兆; 征兆;
superstitious adj. 迷信的; 有迷信观念的;
magpie n. 鹊; 喜鹊;
练习感悟：