Have you ever looked carefully at a snowflake?
在疑问句中表比较，译为“在任何时候”，相当于 at any time
Nobody has ever found a pearl inside a plum stone!
Nothing ever happens.
1.ever 译为“从来”，与 not 连用，译为“从（来）不，从（来）未”
2.ever 译为“从来”，否定句（与否定词 no one，nobody，nothing 等连用），译为“从（来）不，从（来）未”等
I was the biggest man they had ever seen!
ever 与完成时连用，用以强调
1、当与现在完成时连用时，相当于“any time up to now”，例如：You are most beautiful girl I have ever seen.
Have you ever been to Italy?
你去过意大利吗？
It’s the best thing that has ever happened to me.
这是迄今（现在）我所遇到的最好的事。
2、当与过去完成时连用时，相当于“any time up to then”，例如：
Had you ever been to Italy?
你去过意大利吗？
It’s the best thing that had ever happened to me.
这是迄今（说话者的时间）我所遇到的最好的事。