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

Burj Khalifa is a very famous building which is situated in Dubai. Its height is 829,8 metres. It __________________ the tallest building in the world ever since 2009. The number of floors in Burj Khalifa is so huge as there are a total of 2909 stairs from the ground floor to the 160^th floor.