原因是的用法和样例：
例句
-
地震本身的真正原因是地球表面的或地底下的岩石断裂或破裂。
The actual cause of the quake itself is the rupturing or breaking of rocks at or below the earth's surface. -
这个地区疾病的主要原因是水不清洁。
A major cause of the disease in this area is unclean water. -
引发事故的间接原因是火车晚点。
The accident was the indirect result of the train being late. -
你缺席的真正原因是什么？
What was the real reason for your absence?
