Language Points:( 语言点)
1．migrating summer birds: the kinds of birds moving from on region to another seasonally, particularly in summer. (夏季迁徙的候鸟)
migrate: 移居，从一国或地区迁往另一国或地区定居
In recent years, a large part of rural population has migrated to big cities. (近年来，大量农村人口涌入大城市)
Immigrate: vi 移民进来 [例]: He immigrated from China when he was 12 他十二岁时从中国移民到这儿)
2．used to/be used to:
used to: 过去常常… be used to: 习惯于…
[例] 1. She used to walk her pet dog in a nearby park. (她过去常常在附近的公园遛狗)
2．They have been used to the life there with on supply of water and electricity. ( 他们已经习惯了那里没水没电的生活)
3． Marco Polo: an Italian traveler and merchant who had ever been to China in the Yuan Dynasty （马可?波罗：意大利旅行家，商人，元朝期间游历过中国。著有《东方见闻录》将亚洲介绍给欧洲人。）
4． Provide: 提供，供给；常与介词 with 和 for 搭配;与supply 词义、用法接近
[例]；1. The government provides food and clothes for the refugees. The government provides the refugees with food and clothes. (政府向难民提供粮食和衣物)
5.venture
1) v. to risk 冒险，鼓起勇气进行
The expedition ventured further into the jungle. 那支探险队冒险深入丛林里。
Don’t venture too near to the edge of the well;you might fall in . 不要冒险走近井边，太近的话可能会掉下去。
2) n. 尝试，冒险，投机
business venture 商业上的冒险，投机 at a venture 碰运气
6. forth
ad. 向前，向前方 and so on and so forth:等等 back and forth:来回地，往复
He went forth into the desert to pray. 他向前走进沙漠中祈祷。