公园的一头大象一天要吃180千克食物,饲养员准备了3吨食物,够大象吃20天吗?
3吨=3000千克,
180×20=3600(千克)>3000千克;
答:不够大象吃20天.
We all felt a sense of ________ when we saw so many overseas Chinese coming back safe and sound
from Libya. [ ]
A. security
B. relief
C. emergency
D. achievement
什么叫倒闸?什么叫倒闸操作?