Look! Lucy is ________ a new red dress. She is beautiful today.
A:with
B:put on
C:in
D:wear
在△ABC中,D为BC中点,DE⊥AB于E,DF⊥AC于F,已知DE=DF,则下列结论不一定成立的是( )
设i为虚数单位,则复数3+4ii=( )