Alam mo ba kung nasaan ang susi ko?

Filipino does not need a helping verb like English do to form this kind of question.

So:

• Alam mo = you know
• Alam mo ba = do you know?

The predicate often comes first in Filipino, so Alam mo ba... is the normal and natural pattern. The word mo is the short form of you used after the predicate.

Ba is a question particle. It marks the sentence as a yes/no question.

So:

• Alam mo = you know
• Alam mo ba = do you know?

A very common rule is that ba comes after the first word or phrase of the sentence.

Kung introduces an embedded question or indirect question.

In this sentence, kung nasaan ang susi ko means where my key is.

So the structure is:

• Alam mo ba = Do you know
• kung nasaan ang susi ko = where my key is

After verbs like alam (know), Filipino often uses kung before the rest of the question clause.

Nasaan means where is or where are when asking about the location of a specific person or thing.

Examples:

• Nasaan ang libro? = Where is the book?
• Nasaan si Ana? = Where is Ana?

It is a very common word for asking location.

Saan is the general word for where.

Nasaan is more specifically used for asking where someone or something is located.

So:

• Saan = where
• Nasaan ang susi ko? = Where is my key?

In casual speech, you may sometimes hear Saan ang susi ko?, but Nasaan ang susi ko? is fuller and very natural.

Ang is a very important marker in Filipino. It often points to the specific noun phrase being talked about.

Here, ang susi ko means my key as the specific thing whose location is being asked about.

It can sometimes feel similar to English the, but it is not exactly the same. Filipino does not use articles in exactly the way English does. It is better to think of ang as a marker, not a direct one-word translation.

In Filipino, short possessive pronouns like ko, mo, and niya usually come after the noun.

So:

• susi ko = my key
• bahay mo = your house
• kotse niya = his/her car

This is the normal everyday pattern.

Yes, you could, but it sounds more formal, literary, or emphatic.

Compare:

• susi ko = the normal everyday way to say my key
• aking susi = a more formal or expressive version of my key

In ordinary conversation, susi ko is much more common.

Yes. You can say:

Alam mo kung nasaan ang susi ko?

This can still mean Do you know where my key is?, especially in speech, where intonation makes it clear that it is a question.

However, ba makes the yes/no question more explicit, so Alam mo ba... is a very common and clear form.

Yes. That is a perfectly natural sentence.

But it asks a slightly different question:

• Alam mo ba kung nasaan ang susi ko? = Do you know where my key is?
• Nasaan ang susi ko? = Where is my key?

The original sentence asks whether the other person knows the location. The shorter one asks for the location directly.

Some natural answers are:

• Oo, alam ko. = Yes, I know.
• Nasa mesa. = It’s on the table.
• Nasa bag mo. = It’s in your bag.
• Hindi ko alam. = I don’t know.

A full exchange could be:

• Alam mo ba kung nasaan ang susi ko?
• Oo, nasa mesa.

or

• Hindi, hindi ko alam.