in pig短语⁸⁴³²⁰⁺⁸ 基本例句 怀小猪的 Human infections with swine influenza have been detected occasionally since the late 1950s usually in persons with direct exposure to pigse.g. people working in pig farms, etc.. 自20世纪50年代以来，就已经检测到有人类感染猪流感，患者通常和猪有直接的接触例如：猪场工人等。 i21st