发现恒星围绕银河系中心的超大质量黑洞运行是天体物理学的一个转折点。
I do not know much about it, but I think some of America's best young men served in this war.
谁也不能剥夺我们对真理的追求。
Quality should never be compromised, because reputation is built over a lifetime but lost in a moment.