、？
I felt the house shake a little — did you?
Literal
I [topic-は] house [subject-が] a-little shake [nominalizer-の] [object-を] felt [but-が], you [topic-は]?
家が揺れるのを感じた — a perception construction. The trailing が、君は？ is a brilliant conversational fragment: が ('but') opens a contrast, and 君は？ (just 'and you?') invites the listener to share their experience. Likely an earthquake context.