a. lacking stability or fixity or firmness
s. highly or violently reactive
s. disposed to psychological variability
a. 不稳定的
1. The weather is very unstable this week, with sudden rain and sunshine.
这个星期天气非常不稳定，时而下雨时而出太阳。
2. The bridge was declared unstable after the earthquake.
地震后，这座桥被宣告为不稳定。
3. His emotions are often unstable, changing from happy to sad quickly.
他的情绪常常不稳定，迅速从快乐变为悲伤。