half life

half life汉语翻译：
【医】 半衰期(放射性物质), 半存留期(化学性物质)英语解释：
名词 half life:

the time required for something to fall to half its initial value (in particular, the time for half the atoms in a radioactive substance to disintegrate)同义词：half-life

He's been lucky all his life and has never had to find out how the other half lives.他享了一辈子的福，从来不知道穷人生活的滋味。