再加上括号,非真实条件句,我找不到适合的理由

再加上括号,非真实条件句,我找不到适合的理由 (非真实条件句) (非真实条件句)If She was in charge,she would do things differently.变成省略IF 的句子:Were she in charge,she would do things differently.为什么If She was in charge中要用"was"不用"Were"?