一旦冲突被检测出来，它们可即时切换到未用频谱的备份频段。
When a conflict is detected, they switch to a backup slice of unused spectrum on the fly.
通过辨析大部分小行星，研究它们的碎片，天文学家们坚信，一旦有小行星要撞击地球时，他们可提前许多年作出预测。
By identifying most of these asteroids, and plotting their bits, astronomers insist, they could predict many years in advance if any were destined to strike earth.
一旦熊发现我们住的这些模样古怪的大盒子里有东西可吃，门和窗根本就挡不住它们。
'The moment a bear is rewarded by figuring out there's food in these funny boxes we live in, you can't build a door or a window that will keep him out, ' said Mr.
应用推荐