Question

(CH3)3CCHO does not undergo aldol condensation.

Answer 1

For the aldol condensaton, the presence of alpha hydrogen is required. As in the ketone or aldehyde for the aldol condensation there is alpha hydrogen present in it. While in the chemical given in the question, there is no alpha hydrogen , so it can not be condensed. 

Answer 2

The major criteria for a an aldehyde or a ketone to undergo aldol reaction is the presence of alpha hydrogen. As the mentioned compound does not have even a single alpha hydrogen therefore it will not undergo aldol condensation reaction.