There was a man on the news last night who believes we've been visited by beings from other worlds.昨晚的新闻报道中，有个男子认为外星生物曾经拜访过我们。I have always doubted the existence of life on other planets.我一直对外星生物的存在持有怀疑。He wanted to probe the asteroid belt for signs of intelligent alien beings.他想探索小行星带，看看那里是否有迹象表明存在着智能外星生物。