Why we used ce que? And as ce que is what then why we used 'de plus en plus'

Question

In the sentence

Je savais de plus en plus ce que je voulais

Can't it be que instead of ce que

And since ce que is what which means noun why we used de plus en plus and why imparfait is used not passé composé? Also if there is a verb before the blank and a noun after what would we use de plus en plus or de plus en plus de ? If nothing is after then?

Accepted Answer

If you use que (without ce) it needs a definitive noun which is mentioned in the main clause. If it is an implicit idea then you need to use ce que.
Je savais de plus en plus ce que je voulais. -- I knew more and more what I wanted.
The pronoun "what" refers to an idea or concept which is not mentioned in the sentence. Therefore you use ce que.

Answer

All the samples I studied in this lesson uses de before moins et moins, plus et plus. The answer in the test does not use it. When do we use de and when not