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在观察性研究中,我们常常不得不依赖于无法直接检验的假设。
Food security is the cornerstone of national security.
有些天性太过顽固而无法抑制,太过傲慢而不能屈服。
The key to successful investing is to buy stocks at a discount to their intrinsic value and to be patient.
In the examination of the parts of animals, I have diligently endeavored to arrive at the truth.