It also therefore slightly strengthens the challenge those community operating systems can make to Red Hat and Novell, which are more direct commercial challengers to Windows.
这也加强了这些社区操作系统挑战Red Hat与Novell的能力，而后者对于Windows来说是更加直接的挑战者。
The Red Hat exams are an advanced challenge.
红帽考试是高阶挑战。
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