jīng / lì / nà / duàn / kùn / nán / shí / qī / hòu / tā / de / xìn / xīn / yí / dù / diē / zhì / gǔ / dǐ

经历那段困难时期后，他的信心一度跌至谷底。

After going through that difficult period, his confidence hit rock bottom for a while.