Learn Dutch: De bioloog had de verrekijker altijd bij zich. - The biologist always had the binoculars with him.

In Dutch, a pair of binoculars is treated as a single object: de verrekijker (literally a 'far-looker'). You only use the plural verrekijkers if you are talking about multiple pairs of binoculars.

Why does the sentence use zich instead of hem for 'him'?

The Dutch expression for having something on your person is iets bij zich hebben. Because the subject (de bioloog) and the person he has the binoculars with are the same person, Dutch requires the reflexive pronoun zich. If you used hem, it would mean he had them with a different man.

Why use bij zich instead of met zich for 'with him'?

While English uses 'with', Dutch specifically uses the preposition bij to indicate carrying something on your person. The phrase met zich meedragen (to carry along with oneself) exists, but for simply 'having something on you', bij zich hebben is the standard fixed expression.

Why is altijd placed after de verrekijker instead of before it?

In Dutch word order, specific (definite) direct objects like de verrekijker generally come before adverbs of time like altijd. If the object were indefinite, it would come after the time adverb, as in: De bioloog had altijd een verrekijker bij zich.