A: One reason was that Mexico was extremely fortunate, not just to have the US as a neighbor, but to have the US experiencing an unexpectedly vigorous economic expansion.

• 答：其中一个原因是墨西哥当时非常幸运，不但有美国这强大邻国帮助，又正好碰上美国一次出人意表的蓬勃经济扩展。