老师的评语中特别标注了这篇论文中几个明显的抄袭问题。

The teacher ___red-flagged several obvious plagiarism issues in this essay.

频繁的系统崩溃是硬件故障的警示信号。

Frequent system crashes are a ___red-flag for hardware failure.

老师用红笔圈出了作业中的错误以引起注意。

The teacher ___red-flagged the mistakes in the homework with a red pen.