Nie wiem, skąd ona bierze tyle energii, ale wiem, dokąd chce pojechać latem.

I don’t know where she gets so much energy from, but I know where she wants to go in the summer.

Breakdown of Nie wiem, skąd ona bierze tyle energii, ale wiem, dokąd chce pojechać latem.

• ja: I
• ona: she
• ale: but
• nie: not

Questions & Answers about Nie wiem, skąd ona bierze tyle energii, ale wiem, dokąd chce pojechać latem.

Why are skąd and dokąd used here instead of gdzie?

Because they express direction, not just location.

• skąd = from where
• dokąd = to where / where to
• gdzie = where in the sense of location

So:

• Nie wiem, skąd ona bierze tyle energii = I don’t know where she gets so much energy from
• ale wiem, dokąd chce pojechać = but I know where she wants to go

A quick contrast:

• Gdzie ona jest? = Where is she?
• Skąd ona jedzie? = Where is she coming from?
• Dokąd ona jedzie? = Where is she going?

Why are there commas after Nie wiem and before ale?

Polish uses commas in both of those places for standard grammar reasons.

1. Nie wiem, skąd...
   The comma separates the main clause from a subordinate clause introduced by a question word like skąd, dokąd, co, kiedy, dlaczego, etc.

2. ..., ale wiem...
   The comma before ale is required because ale means but, and it joins two coordinate clauses.

So the structure is:

• Nie wiem, skąd ona bierze tyle energii,
• ale wiem, dokąd chce pojechać latem.

Why is ona included? Could it be omitted?