IFEn.内场致放射ifconj.是否；如果；即使；每当n.条件；设想If device has a queue如果设备有一个队列If Heaven Is There IIIf it was a Scotchman苏格兰人If yo like hot dishes您要是爱吃辣if/where applicable如果适用If You Love Her EnoughIf I ever catch him.我要是抓到他的话, 哼(就决不饶他)!if one's ship comes inIF quadrature sampling中频正交采样if the occasion arises必要的时候