"Has been waiting" should be your answer. a simple predicate is the verb or verb phrase in the sentence and it usually tells what the subject does.
The best answer I'm getting out of this is 3. But this is tricky, good luck
1. assess
2. sequence
3. facilitate
4. propaganda
5. assimilate
Okay so none of them actually contain the schwa sound. The closest one to it is precision and thats pronounced (this is from google) prəˈsiZHən
