Many people equate focal ratios with image brightness, but strictly speaking this is only true when taking pictures of "extended" objects like the Moon and nebulae.

许多人常常把焦比和图像亮度等同。其实严格来说，只有当观察月亮和星云等“扩展”光源(译者注：与点光源相对，可以理解为面光源)的时候，上述说法才是正确的。

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ITTAP model of public speaking teaching in class proves that public speaking can be extended as curricular or extracurricular activities with high feasibility and manipulation.

ITTAP演讲教学模式证明英语演讲课程作为英语教学活动的延伸有着很大的可行性与可操作性。

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Generally speaking, most child labor work for extended periods of time performing mundane jobs in decrepit working conditions.

一般来说，大多数童工每天在恶劣的条件下长时间工作。

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Speaking of the extended family, he said that ''even now we can't come to terms or comprehend'' what had happened.

BBC: French Alps murders: Uncle's concerns over police probe

For example, I watched extended live coverage of the Shenzhou-9 mission in my living room in the UK via the English-speaking version of CCTV, the state broadcaster.

BBC: China in space: Running fast to catch up