at fault/in fault

【问】 下面是《大学英语四级考试常见错误分析》(P.6)对at fault与in fault的正误分析：

“误：You were in fault for telling the truth to the poor old lady so early.正： You were at fault for telling the truth to the poor old lady so early.

译：你不该那么早把实情告诉那位可怜的老妇人。

析：at fault=in the wrong，at a loss，inaccurate

My memory was at fault我记错了。

in fault有过错，有责任，Who is in fault for having posted the invitation so late.邀请信这么迟才寄出，是谁的过失?”

您是否同意上面的说法?

【答】 实际上，at fault与in fault在现代英语里并不存在这样的区别。at fault可以表示上面提到的两种意思：

1. It was in 1976，I believe，if my memory is not at fault. (EED)

我认为那是在1976年，如果我没有记错的话。

2. Which driver was at fault(in the wrong)in the car crash? (LASED)

在这次撞车事故中是哪一个司机的过错?

偶而也用in fault来表示上面的两种意思：

1. You were in fault for having been so rude.

你那么粗鲁是不对的。

2. The hound was in fault.

是猎犬的过错。

由此可见，完全没有必要让学生花时间和精力去纠正这样的“错误”。