Это была вторая попытка.

Because in sentences like this, the past-tense form of быть agrees with the main noun phrase, not with это.

Here, the main noun is попытка, which is feminine singular, so the verb is была.

Compare:

• Это был второй шанс. — masculine
• Это была вторая попытка. — feminine
• Это было второе предупреждение. — neuter
• Это были первые шаги. — plural

So even though это may look neuter, it does not control the gender here.

Because вторая describes попытка, and попытка is a feminine noun.

Ordinal numbers such as первый, второй, третий behave like adjectives in Russian, so they must agree with the noun in:

• gender
• number
• case

Here the forms are:

• masculine: второй
• feminine: вторая
• neuter: второе
• plural: вторые

So:

• вторая попытка
• второй шанс
• второе предупреждение

It is in the nominative singular.

That is the normal case here because the sentence is identifying something: This/It was the second attempt.

So both words are nominative singular:

• вторая — feminine nominative singular
• попытка — feminine nominative singular

Here это is a very common Russian word used to point to or identify something. In English, depending on context, it can be translated as:

• this
• that
• it

In a sentence like Это была вторая попытка, it helps set up an identification: This/It was the second attempt.

So это here is not just a simple dictionary this. Its function is more like introducing or identifying what something was.

You can, but it changes the feel of the sentence.

• Это была вторая попытка. = It/This was the second attempt.
• Была вторая попытка. = more like There was a second attempt or a more context-dependent statement

So if you want the same structure and meaning as the original sentence, keep это.

In the present tense, Russian usually omits the verb быть.

So:

• Это вторая попытка. = This is the second attempt.

But in the past tense, the verb appears:

• Это была вторая попытка. = This was the second attempt.

And in the future:

• Это будет вторая попытка. = This will be the second attempt.

So the missing is happens only in the present tense.

Usually, for a basic identifying sentence like this, Это была вторая попытка is the normal choice.

Russian sometimes uses the instrumental case with predicate nouns, especially in other sentence types, but here the nominative version is the most natural and standard for learners.

So learn this as the default pattern:

• Это был...
• Это была...
• Это было...
• Это были...

with the noun phrase in the nominative.

Because Russian has no articles.

So попытка can mean:

• an attempt
• the attempt

and the exact English choice depends on context.

In this sentence, English naturally uses the because second attempt is specific, but Russian does not need a separate word for that.

Yes, Russian word order is flexible, but Это была вторая попытка is the most neutral and natural order.

Changing the order can add emphasis or sound less neutral. For example, different word orders may highlight:

• what it was
• which attempt it was
• contrast with something said earlier

For learners, the original order is the safest and most standard one to use.

The stress is:

Э́то была́ втора́я попы́тка.

Word by word:

• э́то
• была́
• втора́я
• попы́тка

Stress matters in Russian, so it is worth learning words together with their stress patterns.