Одного метра ткани нам не хватит: лучше взять два метра, если мы хотим сшить длинные шторы.

Because не хватит normally takes the thing that is insufficient in the genitive case.

So in Одного метра ткани нам не хватит, the phrase literally works like:

• one meter of fabric → один метр ткани
• but after не хватит → одного метра ткани

Also, один behaves like an adjective, so it changes form to match метр in the genitive:

• nominative: один метр
• genitive: одного метра

So the sentence structure is basically One meter of fabric will not be enough for us.

Because Russian often uses this pattern for measurements:

• метр ткани = a meter of fabric
• чашка чая = a cup of tea
• бутылка воды = a bottle of water

The thing being measured goes into the genitive case. The dictionary form is ткань, but after метр it becomes ткани.

So:

• ткань = fabric
• метр ткани = a meter of fabric

Нам is the dative case of мы, and with хватить / хватать, the person for whom something is enough or not enough is usually in the dative.

So:

• нам хватит = it will be enough for us
• нам не хватит = it will not be enough for us

This is a very common Russian pattern:

• Мне хватит = That’s enough for me
• Тебе не хватает времени = You don’t have enough time
• Нам не хватит одного метра = One meter won’t be enough for us

This is because хватить is a perfective verb. In Russian, perfective verbs do not have a true present tense form. What looks like a present form actually refers to the future.

So:

• хватает = is enough / is being enough, from the imperfective хватать
• хватит = will be enough, from the perfective хватить

That is why:

• Одного метра ткани нам не хватает = One meter of fabric is not enough for us
• Одного метра ткани нам не хватит = One meter of fabric will not be enough for us

In this sentence, the speaker is judging a future result, so не хватит is the natural choice.

The colon links two closely connected ideas:

• first: Одного метра ткани нам не хватит
• second: лучше взять два метра

The second part explains or follows from the first part. In English, this is similar to:

• One meter won’t be enough: it’s better to take two.

So the colon here introduces a conclusion or recommendation based on the first statement.

Лучше + infinitive is a very common Russian way to say it’s better to...

So:

• лучше взять = it’s better to take
• лучше подождать = it’s better to wait
• лучше не спорить = it’s better not to argue

The subject is often left understood from context. Here it clearly means we.

You could also say:

• Нам лучше взять два метра

That makes the for us part more explicit. But лучше взять два метра is very natural and concise.

After the numbers 2, 3, 4, Russian normally uses the genitive singular form of the noun.

So:

• два метра
• три метра
• четыре метра

After 5 and higher, Russian usually uses the genitive plural:

• пять метров
• шесть метров

So the sentence correctly says:

• лучше взять два метра = it’s better to take two meters

This number pattern is one of the most important things to learn in Russian.

Because сшить is perfective, and here the speaker is talking about achieving a finished result: to sew/make the curtains.

Compare:

• шить = to sew, to be sewing, to sew in general
• сшить = to sew and finish, to make completely

So:

• мы хотим шить шторы would suggest the process or activity of sewing curtains
• мы хотим сшить длинные шторы means we want to make a finished pair/set of long curtains

In this sentence, the completed result is what matters, so сшить is the better choice.

It is accusative plural, because сшить takes a direct object: we want to sew what? long curtains.

However, with inanimate plural nouns, the accusative plural looks exactly the same as the nominative plural.

So:

• nominative plural: длинные шторы
• accusative plural: длинные шторы

That is why the form does not change here.

Yes, absolutely. That version is very natural too.

Both are correct:

• Одного метра ткани нам не хватит
• Нам не хватит одного метра ткани

The difference is mostly word order and emphasis.

• Одного метра ткани нам не хватит puts early emphasis on the amount: one meter of fabric
• Нам не хватит одного метра ткани starts with for us, which sounds a bit more neutral in many contexts

Russian word order is flexible, and speakers often move information around to highlight what matters most.

Yes, in this context шторы means curtains, especially the kind used on windows in a home.

So длинные шторы means long curtains.

That fits naturally with the idea of buying fabric and sewing them. A native speaker would immediately understand this as household curtains, not something abstract.

Yes, this sentence combines several very common Russian patterns:

1. Genitive after хватить / не хватить

   • Одного метра нам не хватит

2. Dative for the person affected

   • нам не хватит

3. Measurement + genitive

   • метр ткани

4. 2, 3, 4 + genitive singular

   • два метра

5. лучше + infinitive

   • лучше взять

6. Perfective verb for a completed result

   • сшить шторы

So this is a very useful sentence because it shows several core grammar patterns all at once.