制造链式反应机器的根本点当然是确保每次裂变产生一定数量的中子，其中一些中子将再次产生裂变。
The fundamental point in fabricating a chain reacting machine is of course to see to it that each fission produces a certain number of neutrons and some of these neutrons will again produce fission.
我们不试图把握市场时机。我们试图买便宜的东西。
Coal is not just a commodity, it's a commitment to America's future.
The true essence of a story is not in its plot, but in the emotions it evokes.
阅读未见过的书，如结识好朋友，情意和洽；重读已看过的书，如老朋友相晤，叙旧联谊。