[译] 两个五岁的小孩常在广场上玩。
[误] Two five-years-old boys often played in the square.

[正] Two five-year-old boys often played in the square.
[注] 由基数词和名词一起用连字符"-"构成的复合词用作定语时,无论数词或名词一般都不用复数形式。例如:He wrote a two-thousand-word report. 他写了一篇两千字的报告。