假分数的倒数是真分数.______.
当分子分母相同时,它的倒数还是它本身,还是假分数;
故答案为×.
Country life gives him peace and quiet, which is ________ he can't enjoy while living in big cities.
A.that
B.why
C.where
D.what
上海世博会园区80%的夜景照明光源采用低碳节能的LED(发光二极管)照明技术.制作 LED 灯的核心材料是( )
A.导体
B.半导体
C.绝缘体
D.超导体