The mummified mans clothes had disintegrated _______ completely, but appeared to be mainly of leather and fur.
A. almost B. nearly
答案是 A，为何可以用 almost completely 而不可用 nearly completely？
almost和nearly的差异
1．句法上的差异
almost可以用在any及否定词“no, no one, nobody, never, nothing, none, nowhere 等的前面，而nearly则不能。eg：
There is almost no leadership at all．
但，nearly可以用在否定词not之后，起加大否定陈述有哪些用途，而almost则不能。eg：
Its not nearly so nice．
We dont do nearly enough to help．
almost可以用在以—ly结尾的副词的前面，而nearly则不能。eg：
She said it almost crossly．
Your boss is almost certainly there．
almost可以用在like之前，表示“相似，但不一模一样”或防止说得过于一定；nearly则不能。eg：
It made me feel almost like a hostess．
very，so，pretty可以用在nearly前面，却不可用在almost前面。eg：
We were very nearly at the end Of our journey．
...the American who so nearly won the Open Championship in 1970．
Ive pretty nearly finished．
2．语义上的细微差异
通常情况下，“Its almost five oclock．”和“Its nearly five oclock．”意思大致相同；但有时almost所表示的意思比nearly更接近一些。试比较：
Its nearly ten oclock． .
Its almost ten oclock．
3．语用上的差异
almost是一个“纯”程度副词，而nearly则不然，它同时还传达说话人的某种思想情绪和心理状况。eg：
Its nearly eight kilometers to the ZOO．
到动物园还有将近八公里呢。
It cosplayt me nearly twenty pounds．
它花了我将近20英镑呢。
（引自百度）
红体部分说明，nearly不可以修饰以 ly结尾的副词。这就是为何用almost 修饰completely，而不需要nearly修饰。
