If you surmount a problem or difficulty, you get the better of it by conquering or overcoming it.
If you have a surfeit of something, you have much more than what you need.
If you surmise why something has occurred, you make a guess, offer a possibility, or have a theory about it.
If you are unsurpassed in your field of study, you are the best—period.
The surface of something, such as a lake or a table, is the top layer or part of it.
If you survive something, such as a difficult time or trouble, you manage to make it through or live to tell of it.
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