The Mona Lisa is showing her age, museum curators (馆长) in Paris said while announcing a scientific study of the 500-year-old piece.
The thin poplar wood 1 around Leonardo da Vinci"s painting is showing signs of warping, causing curators at the Louvre "some worry".
The museum has 2 a study to evaluate the Mona Lisa"s vulnerability (易受攻击) to climate changes.
The painting will remain on 3 during the testing, the Louvre said.
"Its state of preservation is 4 the source of some concern," a statement issued by the museum said.
Deterioration (变坏) in its wood panel was "greater than that which has been 5 observed," it added.
The study, to be conducted by the Centre for Research and Restoration of Museums of France, will better 6 what materials the painting is made of.
The painting, whose 7 smile attracts millions of visitors to the Louvre, is displayed behind glass to protect it from 8 changes and camera flashes.
It will be put in a specially 9 room in the Louvre early next year.
The Mona Lisa was painted between 1503-1506 and was thought to be named after the sitter, most likely the Florentine wife of Francesco del Giocondo.
It moved to France with da Vinci in the early 16th Century, where it has 10 except for a short spell when it was stolen in 1911. The painting was discovered two years later in a Florence hotel.
A. mysterious B. previously C. dose D. commissioned
E. charity F. climatic G. intentionally H. redecorated
I. interfere J. display K. determine L. currently
M. panel N. suspicious O. remained