huí / yì / qǐ / nà / duàn / wǎng / shì / tā / xīn / zhōng / fàn / qǐ / yī / zhèn / suān / sè

回忆起那段往事，她心中泛起一阵酸涩。

Recalling that past, she felt a pang of bitterness in her heart.