inner tube
inner-tube的词性:n.(名词)
1. A flexible, airtight hollow ring, usually made of rubber, that is inserted into the casing of a pneumatic tire for holding compressed air.内胎:柔韧密封的内空环形物,通常用橡胶制成,它被嵌入气胎的套子里用来盛装压缩的空气