Jessica, 

The answer to your question is covered in the lesson. Worth reading through again.

With a simple tense and no verb object, you can end with ‘…. pas encore’. 

With a compound tense, or an object following the verb, you can’t place ' pas encore ' at the end of the sentence - 'pas encore' needs to go before the object, or between the auxiliary and the conjugated verb past participle, as the case may be. 

Regardless, you cannot split the expression ‘ pas encore’ itself.