这种方法实现简单，但需要在每个 iOS 调用点手动处理类型转换。
The report pointed out how birth rates in the U.S. have been below the minimum replacement rate since 2008, meaning that the bulk of population growth since then has been the result of immigration. This has proved especially true for the country’s labor force. Nearly 80% of immigrants are of working age, according to the Census, and they account for 19% of the workforce, around 33 million people.
。关于这个话题，爱思助手下载最新版本提供了深入分析
Москвичей предупредили о резком похолодании09:45
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