关于lest,for fear that,in case的虚拟语气用法

凡是由lest（以免；免得）,in case（以防）和 for fear that（生怕,唯恐）引导的目的状语从句中,用“should+动词原形 其谓语部分should可以省略.例如：
Keep quiet in case you（should）interrupt him
when he is busy．要保持安静,以防打扰他.
She is now studying for fear that she（should）fail in
English．她现在很勤 奋,生怕英语不及格.
You must wake him early lest he（should）be late for
school．你务必早点叫 醒他,以免他上学迟到.
三个都能省的.

lest、for fear that和in case引导的从句用虚拟语气，其谓语部分用“should+动词原形”。
其中，lest和for fear that引导的葱郁，可以省去should，但是in case引导的从句，如果表示虚拟，should一般不可省略！

1.在for fear that, in case, lest引导的从句中，若用虚拟语气时，从句谓语为：should + 动词原形。并且 should不能省略 She examined the door again for fear that a thief should come in. 她又把门检查了一遍，以防盗贼的进入。 He started out earlier lest ...

lest: 惟恐 = in case假使，免得
I was afraid to open the door lest he should follow me...
And, lest we forget, Einstein wrote his most influential papers while working as a clerk.
for fear of, f...

in case 一定不能省should
另两个可省
貌似不同语法书说法不同
保险点你就别省了呗