A:30°
B:45°
C:60°
D:90°
将维生素主要与生理作用、其对应的缺乏症用直线连接起来
A.促进伤口愈合____ ①维生素A
B.促进骨骼发育____ ②维生素B
C.脚气病____ ③维生素C
D.夜盲症____ ④维生素D
如图所示,为潜望镜的结构示意图,通过这样的潜望镜看到物体AB的像是( )
— Will you buy this tie for Dad?
— I have no idea. I don’t know or not the colour matches his new shirt.