Hi @Anonymous,
Hope you are well! 
It is difficult to say exactly what they might ask you in an interview when applying for the positions which you mentioned. Generally, companies will provide you with a test focused on the discipline which you are applying for. The test will then primarily test your software knowledge along with discipline design knowledge. This will normally happen prior to an interview as in an interview (in my opinion), the person conducting the interview will generally look at you as a person and your career/project experience along with qualifications (which will be outlined in your CV in any case). You might get someone who conducts an interview who might ask software related questions, but that is rare (in my opinion) as the test would have provided them with information relating to your software knowledge/experience.
This seems as it was unfortunately not the case with you, so to prepare yourself for answer which might come up, I would suggest that you go through some of the following articles below as they can literally ask anything. Some of the basic questions in tests relating to HVAC (mechanical discipline in Revit) will be covered in the articles below: (Also make use of the vertical menus to the left and any related topics or links).
Create Supply, Return, and Exhaust Duct Systems
Creating Piping Systems (Aslo Google "Fire Protection and Hydronic Systems in Revit")
Heating and Cooling Loads Reports
Building Type Settings
Space in Revit
Generic Parts to Fabrication Parts
MEP Modeling
Shared Parameters in Revit
Have a look at the second page of THIS LINK and make sure that you understand and know how to do each of the listed tasks under each of the main categories.
This should get you started and might help to ensure that you are a bit more confident in answering questions in an interview. We might be able to provide you with a list of questions which might come up, but none of those questions might be asked in your interview. The best thing would be to read up a bit to ensure that you are prepared/educated in a "broad spectrum"...
I hope this helps! 
Rudi Roux
MSc | Digital Engineering Manager
LinkedIn
Revit Mechanical & Electrical Systems 2018 Certified Professional | Revit MEP & Architecture 2015 Certified Professional
AutoCAD 2015 Certified Professional | Autodesk Building Performance Analysis (BPA) Certificate
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