T: 原因是 S: 原因是 [yuan2 yin1 shi4] = the reason is ...
當小孩有學習障礙時,往往很難確定原因是什麼。
当小孩有学习障碍时,往往很难确定原因是什么。
dang1 xiao3 hai2 you3 xue2 xi2 zhang4 ai4 shi2, wang3 wang3 hen3 nan2 que4 ding4 yuan2 yin1 shi4 shen2 me5.
When children have learning difficulties, it is often difficult to pinpoint the cause of the problem.
https://www.learnwitholiver.com/chinese/daily-sentence-3974