Пре­об­ра­зуй­те, если это не­об­хо­ди­мо, слово BE так, чтобы оно грам­ма­ти­че­ски со­от­вет­ство­ва­ло со­дер­жа­нию тек­ста.

When Peter came home from work he immediately felt that something was wrong. He was sure that somebody __________________ in his house in his absence.