the he cut off the leather shoe as if it _(be)the finest steak.为什么答案是were

在描述过去一件事情（过去时）时用 It be 表示假设（虚拟语气）,通常用 It were.而 It was 则多用于现在时的假设句中.例：
He gets up exactly at 6 o'clock in the morning as if it was a clock in his head that woke him up.