origin of element

例句：

1. 1.The origin of the species is still a mystery to scientists.
   物种的起源对科学家来说仍然是个谜。
2. 2. The origin of this disease has not been fully understood.
   这种病的原因尚未完全理解。
3. 3. The origins of the civilization can be traced back thousands of years.
   这个文明的起源可以追溯到几千年前。