Beat and win

Both beat and win are irregular verbs.

Beat – beat – beaten
Win – won – won

You can win a prize or money. You can also win in a game or a battle.

Alice won the first prize.
She always wins when we play poker.

You can beat a person that you are playing or fighting against.

Compare

Alice beat John to win the first prize. (NOT Alice won John to win the first prize.)
She always beats me when we play poker. (NOT She always wins me when we play poker.)

Because and because of

Because is a conjunction. It is usually used at the beginning of a clause before a subject and verb.

We didn’t go out because it was raining.
She was happy because she won the prize.

Because of is a two-word preposition. It is used before a noun or a pronoun.

Compare:

We didn’t go out because of the rain.

Because and its clause can go either before or after the main clause.

He went abroad because he won a scholarship.
Because he won a scholarship, he went abroad.

Begin and start

Begin and start have similar meanings.

She started/began writing when she was 10.

Note that begin is more common in a formal style.

Cases where begin is not possible.

We do not normally begin a journey. We start it.

We started in the morning. (NOT We began in the morning.)

Start, and not usually begin, is used with machines.
How do you start the washing machine? (NOT How do you begin the washing machine?)

Beside and besides

Beside means ‘at the side of’ or ‘next to’.

She sat beside her children. (= She sat next to her children.)

Besides has a meaning similar to as well as.

Besides mathematics, we study physics and chemistry.