suǒyǒu shícái dōu mǎiqí le.

都 is used because 所有食材 means all the ingredients, and 都 often goes with words like 所有, 全部, or plural subjects to emphasize all of them.

A very common pattern is:

所有 / 全部 + noun + 都 + verb / adjective

So here:

• 所有食材 = all the ingredients
• 都买齐了 = have all been bought completely

Even though English does not need a separate word like 都 here, Chinese usually does.

买齐 means to buy everything needed so that the set is complete.

So:

• 买 = buy
• 齐 = complete, all there, lacking nothing

Together, 买齐 suggests not just that some shopping happened, but that everything on the list is now fully bought.

Compare:

• 食材买了。 = The ingredients were bought.
  
  • This does not clearly say whether everything was bought.
• 食材买齐了。 = The ingredients have all been bought; nothing is missing.

So 齐 adds the idea of completeness.

Here, 了 marks a new situation or completed action. In this sentence, it shows that the buying process has reached its result: now all the ingredients are bought.

So 买齐了 means something like:

• have finished buying everything
• are now fully bought

This final 了 is very natural when reporting that something has been accomplished.

Yes, in this sentence 所有食材 functions as the topic/subject-like element: as for all the ingredients...

Then the rest says what happened to them:

• 都买齐了 = all got bought completely / have all been bought

In natural English, we might say:

• All the ingredients have been bought.
• We’ve bought all the ingredients.

Chinese often allows this kind of result-focused wording without explicitly stating who did the buying.

Chinese often omits the subject when it is obvious from context.

So instead of saying:

• 我们把所有食材都买齐了。

it is very common to simply say:

• 所有食材都买齐了。

This sounds natural if everyone already knows who did the shopping, or if the important point is the result, not the doer.

Yes. A very common version is:

我们把所有食材都买齐了。

This version explicitly includes:

• 我们 = we
• 把所有食材 = takes all the ingredients as the object being dealt with
• 都买齐了 = bought them all completely

The original sentence without 把 is more concise and focuses on the finished state. Both are natural, but they emphasize things a little differently.

Because 所有 can directly modify a noun.

So you can say:

• 所有食材 = all ingredients
• 所有东西 = all things
• 所有问题 = all questions

You do not need a classifier here.

However, with some other expressions of all, classifiers may appear depending on the structure.

They are very similar, and both can mean all the ingredients.

In many contexts:

• 所有食材 sounds slightly more neutral and common in general writing/speech.
• 全部食材 also means all the ingredients, sometimes with a slightly stronger sense of the entire amount.

In this sentence, either could work:

• 所有食材都买齐了。
• 全部食材都买齐了。

But 所有食材 is very natural.

In Chinese, 都 usually comes after the subject/topic and before the predicate.

So the structure is:

所有食材 + 都 + 买齐了

not:

• 都所有食材买齐了 ❌

Think of 都 as marking that the whole subject/topic is included in what follows.

Yes. 齐 is often used as a result complement to show that something has become complete or all together.

Examples:

• 找齐 = find all of them
• 备齐 = prepare everything needed
• 凑齐 = gather enough / collect a complete set
• 收齐 = collect all of something
• 买齐 = buy everything needed

So 齐 often gives the sense of nothing is missing now.

Not exactly in form, but it can feel passive in English.

Chinese does not need a passive marker here. The sentence simply states the result concerning all the ingredients. In English, the natural translation is often passive:

• All the ingredients have been bought.

But in Chinese, the sentence itself is not necessarily a formal passive sentence like one with 被.

Yes, absolutely.

Both are natural:

• 所有食材都买齐了
• 所有的食材都买齐了

The version without 的 is a little more compact and very common. Adding 的 can sound slightly more explicit, but the meaning stays the same.