The new school _________ in the past five years.
A:built
B:has been built
C:has built
D:will be built
如图所示,平行板电容器与灯泡串联,接在交流电源上,灯泡正常发光,则( )
“碧玉妆成一树高,万条垂下绿丝绦.不知细叶谁裁出,二月春风似剪刀.”这诗句所说的“绿丝绦”是下列哪一结构直接发育来的( )