It would seem that someone left the building unlocked.
WORD CHOICE: WORD CHOICE: seem, appear, look, soundSeem and appear have the same meaning but appearis more formal• They seem upset. • This appears to be a good solution.You use lookto say how someone or something seems to you when you look at them• Maureen looked tired. • That book looks good. You use soundto say how someone or something seems to you when you hear or read about them, or hear them• She sounds a lovely person. • The party sounded great.• He sounded tired.GRAMMARSeemcan be followed by an adjective or an adjective and noun• She seemed happy. • He seems a nice man.Seemcan also be followed by a verb in the infinitive• His story seems to be true. • You seem to think it's my fault.!! Seem can be followed by as iforas thoughbut not just by as• It seems a small thing (NOT it seems as a small thing), but it's very important. • It seemed as if he wanted us to leave (NOT it seemed as he wanted ...).
Definition from the Longman Dictionary of Contemporary English Advanced Learner's Dictionary.