fault line
noun [ C ] uk/ˈfɒlt ˌlaɪn/ us/ˈfɑːlt ˌlaɪn/
(CRACK)
（地球表面的）断层线
a fault (= a break in the earth's surface)
(PROBLEM)
（潜在的）问题，隐忧
a problem that may not be obvious and could cause something to fail
The fault lines of imperfect peace deals are already showing. 因和平协议不完善而引发的潜在问题已经开始显现。