关于正则表达式的问题

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System.out.println(Pattern.matches("[AA]{2}\\s[BB | CC]{2}.*$", "AA BB"));//true
System.out.println(Pattern.matches("[AA]{2}\\s[BB | CC]{2}.*$", "AA CC DD EE FF GG"));//true
System.out.println(Pattern.matches("[AA]{2}\\s[BB | CC]{2}.*$", "AA ZZ DD EE FF GG"));//false
System.out.println(Pattern.matches("[AA]{2}\\s[BB | CC]{2}.*$", "XX BB DD EE FF GG"));//false
System.out.println(Pattern.matches("[AA]{2}\\s[BB | CC]{2}.*$", "BB CC DD EE FF GG"));//false