Answer:
Under-Stand
Under-Ground
Dis-Like
Im-Possible
Un-Tie
Un-Happy
Re-do
Re-Read
Explanation:
These are the new words that can be created from the given prefixes and root words. Every permutation combination applied and still 2 (Be and Pre) prefixes cannot be attached to make a new word. Another shortcoming is with 1 root word (Slide).
This is because slide is an intransitive verb, that is to say it is a working verb and thus does not need a prefix.
