高中英语语法!（比较有难度）

高中英语语法!（比较有难度）
1.be available for/to 的区别?
2.Shanghai as (a/the) population of over 16 million.(choose one and say why)
3.The official mascots of the 2004 Olympic Games were Athena and Phevos,___________________(A that of both B of which both)为什么选B?（解释请详细）

1.差别是：be available to sb
be available for sth
2.选择A 当你想要表达有着一个多少人口的城市和国家的时候要用a population of ,但是当你要表达某地、某国的人口是多少的时候（强调人口数额）,要用the population of .举个例子就明白了
The population of Beijing is 3000,000.
Beijing is a city with a population of 3000,000.
3.选择B of which both= both of which,因为是非限制性定语从句,所以不能用that引导
希望有所帮助,