Next February 2nd has been dubbed "D-Day" by many computer scientists, with the world expected to run out of IP address blocks at that time.

明年2月2日被许多计算机科学家称为“D日”，预计那时世界上所有IP地址将用完。

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Many stumbling blocks remain, however, including the added costs of filming and broadcasting 3-d images.

当然还有很多障碍，包括增加电影和播出三维影象的预算。

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People with dark skin produce less vitamin D because the skin pigment blocks ultraviolet light from the sun.

深色肤色的人因色素阻止紫外线的吸收而产生的维生素D较少。

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C.O.P.D.,chronic obstructive pulmonary disease, blocks airflow through the lungs.

VOA: special.2009.06.03

"We're now seeing stability in the C and D blocks, " says Arbogast.

FORBES: Google Likely Out, And Happy

And when you'd think it was going to run out, there'd be four or five damaged houses in three or four blocks, you thought, well, you'd kind of come to the end of it, then the next 15 blocks there'd be nothing.

NPR: Hurricane Recovery Efforts in Mississippi

And the first rumblings of a rights-management system for controlling the sharing of physical things are appearing: The IP-hoarding firm Intellectual Ventures received a patent in October for a 3-D printer feature that blocks the creation of verboten objects.

FORBES: Inside Thingiverse, The Radically Open Website Powering The 3D Printing Movement