春天柳树发出的枝条非常柔韧，这是因为下图中的哪一部分结构比较发达（ ）
A．①
B．②
C．③
D．①和②
答案：A
试析英属北美殖民地和西属拉丁美洲殖民地在社会、文化方面的区别，及对南北美洲独立国家的影响。
My sister-in-law___________ my brother for ten years.
A．married with
B．has married
C．has been married with
D．has been married to
