も meaning in もう八日*も*何も食べていないんです。

Question

Here is the full sentence:

すみませんが、水を下さいませんか。
もう八日も何も食べていないんです。

I am still at the beginner level. From my understanding:

もう means already
も means also

Why add も after the もう八日?

Answer 1

It is an emphasis (cf. も #5), and add as many as in the example. As such, も can be dropped but perhaps it is better to add 間 (八日間{ようかかん}) to make it work adverbially.

Another example:

• 日本に来てもう10年経った 10 years have passed since I came to Japan
• 日本に来てもう10年も経った As many as 10 years have passed since I came to Japan