A:钢铁工业
B:煤炭工业
C:石油工业
D:纺织工业
已知⊙O的半径长为50cm,弦AB长50cm.求:点O到AB的距离
Travelling to London
We think ⑴ is the best season to visit England.
We did most of our sightseeing(观光) ⑵ .
The best part of the trip was going to the theatre.
We don't think the English food is very ⑶ .
Jack is an intelligent pupil, but he lacks m____ (主动性).
图中①②是我国两个省区,它们的简称分别是