题目内容
This problem may lead to more serious ones if ____ unsolved.
A、making B、remained C、keeping D、left
A. making B. remained C. keeping D. left
This problem may lead to more serious ones if _____ unsolved.
A. making B. left C. remained D. keeping
These problems may lead to more serious ones, if unsolved.
A. remained B. keeping C. left D. making
