Exact match keywords allow ads to show onlu when the wuery is the same as your keyword.
Phrase match keywords allow ads to show only when the query contains your keyword.
Both exact and phrase match can show for misspelling, sungulars, plurals, different word endings but not for different words.
Broad match words can show an ad when the search query is related to the keyword.
Negetive keywords stops your ads from showing.It does not match to various endings, singulars, plurals and misspellings.
The search terms report shows you actual search query data.
You can use the report to modify or update keywords in your account.