易兴奋性

例句：

1. 1. He is very sensitive to changes in the environment, which makes him easily excited.
   他对环境变化非常敏感，这使得他很容易兴奋。
2. 2. The child's excitement was contagious, and everyone around her became easily excited.
   孩子的兴奋是传染的，周围的人都变得很容易兴奋。
3. 3. The researcher found that certain chemicals could cause an animal's system to become easily excited.
   研究人员发现某些化学物质可以使动物的系统变得很容易兴奋。