Two UAN - if I don't give UAN will they able to find out about previous employment?

I worked in company A and left after working for 3 year then joined another company B(I transferred pf to Company B ) but due to some issue I left Company B (worked for year). Now join Company C if I don't give UAN will they able to find out. I don't want to show I worked with Company B.
Please ans me ASAP.

In the form 11 (Declaration form) if you mention as you didn't have PF account or UAN then it will be difficult to find out. But still its better to continue the same account.

I joined company C without mentioning Company B in resume will I face any problem in future. ?