现状及存在的问题
status and problems
status quo and existing problems
存在现象学
existential phenomenology
燃料乙醇的现在和未来
The present and future of fuel ethanol
有效及现存的汇票
valid and subsisting bill
2π周期解的存在性和唯一性
existence and uniqueness of 2π-periodic solution
Hg的存在形态
mode of occurrence of mercury
本地存在的野病毒
Acute paralytic poliomyelitis wild virus
不存在的
non-existent
Available enrichment coefficient
nonexistent
inexistent
beingless
null
naught