wǒ mǎi le yángròu.

Here 了 is an aspect particle. It shows that the action of 买 has been completed.

So:

• 买 = buy / to buy
• 买了 = bought / completed the act of buying

A very important point: 了 does not simply equal the English past tense. It focuses on the action being done, not just on when it happened.

No. That is one of the most common beginner misunderstandings.

In this sentence, 买了 will often be translated into English as bought, but 了 really marks completion, not past tense by itself.

For example:

• 我昨天买了羊肉。 = I bought mutton yesterday.
• 我明天买了再告诉你。 = I’ll tell you after I’ve bought it tomorrow.

So 了 can appear in sentences that are not purely “past tense” in the English sense. It is better to think of it as marking a completed event.

Because this 了 is attached to the verb.

Basic pattern:

• Subject + Verb + 了 + Object

So:

• 我 + 买 + 了 + 羊肉

This is the normal way to mark a completed action when the verb has an object.

Compare:

• 我吃了饭。 = I ate / have eaten a meal.
• 他看了书。 = He read the book / did some reading.

Both can be natural, but they are not exactly the same.

我买了羊肉

This mainly emphasizes that the buying action was completed.

我买羊肉了

Sentence-final 了 often suggests a new situation or change of state:

• now I’ve bought mutton
• now the situation is that I buy/bought mutton

In real life, context matters a lot, and sometimes both are possible. But as a beginner, a useful rule is:

• verb + 了 = completed action
• sentence-final 了 = new situation / change / updated state

Sometimes both can appear:

• 我买了羊肉了。

But that is more context-dependent and not the best first pattern to memorize.

Yes, but the meaning becomes less specifically “completed.”

我买羊肉 can mean different things depending on context, such as:

• I buy mutton.
• I am buying mutton.
• I will buy mutton.
• I buy mutton in general.

Mandarin often relies on context more than English does.

So if you want to clearly show that the buying is already done, 我买了羊肉 is much better.

Mandarin does not use articles like English does.

English needs words such as:

• a
• an
• the
• sometimes some

Mandarin usually does not.

So 羊肉 by itself can mean things like:

• mutton
• some mutton
• the mutton

The exact meaning depends on context.

If you want to be more specific, you can add other words:

• 一些羊肉 = some mutton
• 那羊肉 = that mutton
• 这羊肉 = this mutton

Because 羊肉 here is being used as a mass noun in a general, non-counted way.

In Mandarin, measure words are usually needed when you count or specify an amount:

• 一斤羊肉 = one jin of mutton
• 一些羊肉 = some mutton
• 一块羊肉 = a piece of mutton

But if you are simply talking about the substance in general, no measure word is necessary:

• 我买了羊肉。

That is completely natural.

Literally:

• 羊 = sheep/goat type animal
• 肉 = meat

So 羊肉 means sheep meat, and in most learning materials it is usually translated as mutton or sometimes lamb, depending on context.

A few things to know:

• In everyday Chinese, 羊肉 usually refers to the meat you would normally think of as mutton/lamb.
• If you need to be very specific, Chinese can specify the kind of animal more clearly.

For a beginner, it is perfectly fine to understand 羊肉 as mutton/lamb.

Mandarin basic word order is usually:

• Subject + Verb + Object

So:

• 我 = subject
• 买了 = verb phrase
• 羊肉 = object

That gives:

• 我买了羊肉。

This is similar to English word order in a simple sentence:

• I bought mutton.

Mandarin is often quite strict about keeping the verb before the object in basic statements.

Yes, there is a tone change here.

Individually:

• 我 = third tone
• 买 = third tone
• 了 = usually neutral tone here

When two third tones come together, the first one usually changes in pronunciation to a rising tone, similar to a second tone.

So 我买 is pronounced more like:

• wó mǎi

Even though it is still written wǒ mǎi in pinyin.

And 了 here is light and unstressed:

• wó mǎi le

This is very normal Mandarin pronunciation.

Sometimes yes, if the context already makes it clear who is doing the action.

For example, in conversation:

• 买了羊肉。 = Bought mutton.

This can sound natural if everyone already knows you are talking about yourself.

But if you are learning, it is safer to keep the full sentence:

• 我买了羊肉。

Mandarin often drops subjects when they are obvious, but beginners should first get comfortable with the complete structure.

Time words usually go before the verb, often after the subject.

Pattern:

• Subject + Time + Verb + 了 + Object

Examples:

• 我昨天买了羊肉。 = I bought mutton yesterday.
• 我今天买了羊肉。 = I bought mutton today.
• 我刚才买了羊肉。 = I just bought mutton.

So if you want to add time, put it before 买了.

Not if the amount is important. Then you would normally include it.

For example:

• 我买了一斤羊肉。 = I bought one jin of mutton.
• 我买了一些羊肉。 = I bought some mutton.
• 我买了一块羊肉。 = I bought a piece of mutton.

But if the amount does not matter, 我买了羊肉 is perfectly natural. It just states the action and the item bought, without specifying quantity.