"She bought what she needed last night" 与 "She bought whatever she needed last night" 有什麼分别?

1.She bought what she needed last night.
2.She bought whatever she needed last night.

whatever=no matter what
so:
1=she bought the things that she needed

2=she bought (all) the things that she needed.

句一是买了一些东西，但是需要的东西没全买。

句二是只要是需要的，就都买了。差别很大。

类似数学里面充分不必要和必要不充分的关系。

1.She bought what she needed last night.

你这句话的grammar 说错了
应该是：She bought what she need last night .
(不需要加 -ed)

你的第二句话也有错误
2.She bought whatever she needed last night.
这个句子里不需要用到“whatever” .

正确的翻译是：

她昨天晚上把需要的东西都买起了。

1,昨晚她买了自己需要的东西
2，昨晚她把自己需要的东西都买齐了
whatever是说无论什么，就是指要买的所有东西

whatever 是what的强调形式。指的是买了所有需要的东西。