Hi Steve,The bower be sign is used in begin and bemuse because they are separate syllables. They are not used in best, better, etc. because the letters b and e are part of a syllable. When the letters en are followed by a comma or period they are read as en. If you are writing the word enough followed by a lower cell sign you need to write enough to avoid ambiguity and lessen confusion.
I hope this helps. Colleen Roth
