Ich nehme das Buch vom Tisch.

Because the subject is ich. The verb nehmen is conjugated like this in the present tense:

• ich nehme
• du nimmst
• er/sie/es nimmt
• wir nehmen
• ihr nehmt
• sie/Sie nehmen

So with ich, the correct form is nehme.

A useful detail: nehmen is a stem-changing verb, but the vowel change to i only happens in du and er/sie/es forms, not with ich.

Das Buch is the direct object of the sentence — it is the thing being taken.

In German, the direct object usually goes in the accusative case. The noun Buch is neuter, and the article das is the same in both nominative and accusative:

• nominative: das Buch
• accusative: das Buch

So the case changes grammatically, but here you do not see a different article form.

Vom is a contraction of von dem:

• von dem → vom

This contraction is very common and usually preferred in normal speech and writing when it sounds natural.

So vom Tisch = von dem Tisch.

Because the preposition von always takes the dative case.

The noun Tisch is masculine, and the masculine dative singular article is dem:

• nominative: der Tisch
• accusative: den Tisch
• dative: dem Tisch

Since von requires dative, you get:

• von dem Tisch
• contracted: vom Tisch

So:

• von den Tisch is wrong because den is not the correct article here
• von der Tisch is wrong because Tisch is masculine, not feminine

German chooses different prepositions depending on the kind of location.

• von is used for movement from a surface, person, source, or general point
• aus is used for movement out of the inside of something

So:

• vom Tisch = from the table / off the table
• aus der Tasche = out of the bag
• aus dem Zimmer = out of the room

Because a book is being taken from the top of a table, von is the natural choice.

Yes, very often that is the best way to think of it.

In this kind of sentence, von often corresponds to English from or off when something is removed from a surface.

So English might say:

• I take the book from the table
• I take the book off the table

German uses vom Tisch for that idea.

Because in German, all nouns are capitalized.

So:

• ich is not capitalized in the middle of a sentence because it is a pronoun
• Buch is capitalized because it is a noun
• Tisch is capitalized because it is a noun

This is one of the most noticeable spelling differences between German and English.

Yes. The German present tense often covers both meanings.

Depending on context, ich nehme can mean:

• I take
• I am taking

German does not usually need a separate progressive form like English am taking. If the ongoing action needs to be especially clear, German normally relies on context or adds extra words.

Yes, German word order is flexible, but this sentence uses a very normal, neutral order.

Here the structure is:

• Ich = subject
• nehme = verb
• das Buch = direct object
• vom Tisch = prepositional phrase showing where from

This order sounds natural and straightforward.

Other orders are possible, but they usually change the emphasis. For example:

• Vom Tisch nehme ich das Buch.
  This puts more focus on from the table.

So the original sentence is a standard, unmarked way to say it.

Yes. It is grammatically correct.

• Ich nehme das Buch von dem Tisch.
• Ich nehme das Buch vom Tisch.

Both mean the same thing. In everyday German, vom is simply the more usual and natural form.

Yes: besides its conjugation, it is also a very common verb with a broad meaning.

In this sentence, nehmen means something like take, pick up, or remove. It often describes physically taking hold of something.

It is different from some related verbs:

• holen = go and get
• bringen = bring
• tragen = carry
• bekommen/kriegen = receive/get

So nehmen focuses on the act of taking the book itself.