Wir sehen eine Linie.

Because wir means we, and the verb has to match the subject.

The infinitive is sehen = to see.
Its present-tense forms are:

• ich sehe = I see
• du siehst = you see
• er/sie/es sieht = he/she/it sees
• wir sehen = we see
• ihr seht = you all see
• sie/Sie sehen = they/you (formal) see

So wir sehen is the correct match for we see.

In a normal German main clause, the conjugated verb usually comes in second position.

So the basic pattern here is:

• Wir = subject
• sehen = finite verb
• eine Linie = object

That gives:

Wir sehen eine Linie.

English also often uses subject + verb + object, so this sentence is nicely parallel to English.

Because Linie is a feminine noun.

The indefinite article a/an changes according to gender:

• ein for masculine and neuter in the nominative
• eine for feminine

So:

• eine Linie
• eine Straße
• eine Lampe

Since Linie is feminine, it takes eine.

It is in the accusative case because it is the direct object of the verb sehen.

Ask yourself: What are we seeing?
Answer: eine Linie

That makes eine Linie the thing being seen, so it is the direct object.

With a feminine noun, the indefinite article is:

• nominative: eine
• accusative: eine

So in this sentence, the form looks the same, even though the case is accusative.

In German, noun gender is something you usually have to learn with the noun.

A good habit is to learn nouns with their article:

• die Linie = the line

If the dictionary form is die Linie, then you know it is feminine.
That is why the indefinite form becomes eine Linie.

Because all German nouns are capitalized.

So:

• Linie is capitalized because it is a noun.
• wir and sehen are not nouns, so they are normally lowercase.

At the beginning of a sentence, the first word is capitalized anyway, which is why you see Wir with a capital W.

A careful pronunciation would be roughly:

veer ZAY-en EYE-nuh LEE-nee-uh

A more precise guide:

• Wir sounds a bit like veer
• sehen sounds like ZAY-en
• eine sounds like EYE-nuh
• Linie sounds like LEE-nee-uh

A useful note: the w in German sounds like English v, and the z in German sounds like ts.

Often yes, but not always perfectly one-to-one.

In this sentence, sehen simply means to see in the visual sense.

German also uses sehen in expressions like:

• Ich sehe dich. = I see you.
• Wir sehen das Problem. = We see the problem.
• Mal sehen. = We’ll see / Let’s see.

So it works a lot like English see, but you should still learn expressions as you meet them.

Yes. Linie can refer to several kinds of line, depending on context, for example:

• a drawn line
• a line in a pattern or diagram
• a route or transport line
• a line of thought in some contexts

But in a simple learner sentence like Wir sehen eine Linie, the most natural interpretation is usually a visible line, such as one on paper or on a screen.

Yes, but it changes the emphasis.

Wir sehen eine Linie. is the neutral, standard sentence.

Eine Linie sehen wir. puts extra focus on eine Linie, almost like:

A line is what we see.

German allows this kind of reordering more than English does, but the finite verb still stays in second position in a main clause.

Because eine already means a/an.

So:

• eine Linie = a line

If you wanted the line, you would say:

• die Linie

German articles carry a lot of information: gender, number, and sometimes case. So even a small word like eine is doing important grammatical work.