他们在董事会期间悄悄交换了微笑，小心不让主席发现。
They exchanged covert smiles during the board meeting, careful not to let the chairman notice.
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解释
covert 在此指刻意隐藏、不让他人察觉的表情交流。
They exchanged covert smiles during the board meeting, careful not to let the chairman notice.
covert 在此指刻意隐藏、不让他人察觉的表情交流。