Learn Dutch: De man scheert zich bij de spiegel.

In Dutch, shaving is a reflexive action. The full verb is zich scheren (to shave oneself). Even though in English we usually just say 'the man shaves', in Dutch you must include zich (himself) to show who he is shaving.

What would this sentence look like if I wanted to say 'I shave by the mirror'?

The reflexive pronoun changes to match the subject. If you are doing the shaving, you use me (myself). The sentence becomes: Ik scheer me bij de spiegel. For 'you', it would be: Jij scheert je bij de spiegel.

Why does scheert have two 'e's, but the dictionary form scheren only has one?

This is a spelling rule to keep the vowel sound long. In scheren (sche-ren), the first syllable is open, making the 'e' naturally long. In scheert, the syllable is closed by the letters 'r' and 't'. To keep the same long 'e' sound, we have to double the vowel.

Can bij be used to mean 'at' as well as 'by'?

Yes! Bij is a very common preposition that can mean 'by', 'near', or 'at' depending on the context. Here, bij de spiegel means 'by the mirror' or 'at the mirror'.