“预期寿命”常见的英文表达是 “life expectancy” 。
例如:
The average life expectancy in this country has increased over the past decade.(过去十年间,这个国家的平均预期寿命有所增加。)
Advances in medical technology have contributed to a rise in life expectancy.(医疗技术的进步促进了预期寿命的提高。)