In order to find the real__of bird flu,scientists spent a large a_英语解答

In order to find the real__of bird flu,scientists spent a large amount of time on it.
(reason/cause)选哪个
为什么

人气：363 ℃　时间：2020-04-04 03:17:17

解答

cause.
reason指做一件事的理由,而cause侧重于事件的起因.