step change
noun/ˈstep tʃeɪndʒ/
/ˈstep tʃeɪndʒ/
[usually singular] (British English)- a big change or improvement in something
巨大变化；显著进步（或改善） - His speech called for a step change in attitudes to the environment in the 21st century.
他的演讲呼吁在 21 世纪彻底改变对待环境的态度。
- His speech called for a step change in attitudes to the environment in the 21st century.