Possible Clues:

• Sing -- (vocalize alone)
• Sing -- (croon alone)
• ''Surgery is __ act'': ''Grey's Anatomy''
• Do ___ (perform alone)
• Italian town NW of Venice
• Embark on ___ career
• Sing -- (perform an aria, e.g.)
• 'Pippa Passes' setting
• Sing -- (croon by oneself)
• Sing -- (vocalize by oneself)