1. For example, they do not compensate for social inequality, and thus do not tell how able an underprivileged youngster might have been had he grown up under more favorable circumstances.
分析:本句中 had he grown up under more favorable circumstances 属于部分倒装。正常语序为: if he had grown up under more favorable circumstances 。在正式文体中,可以将虚拟条件句中的 if 省略,并将助动词提前。
2. Nonstop waves of immigrants played a role, too and so did bigger crops of babies as yesterday’s “baby boom” generation reached its child-bearing years.
分析:该句中 so did bigger crops of babies 属于语法倒装。用 so 来代替前述肯定句谓语部分所说情况。