A:addicted to
B:addicting i
C:addicted himself i
D:been addicted to
如图所示,将长方形ABCD的纸片沿EF折叠,点D、C分别落在点D′、C′处,若∠AED′=50°,则∠EFB的度数为____.
请认真观察漫画,回答下列问题: