它能在30秒内硬化为泡沫，在几小时内变为柔韧的皮质。
It solidifies into a foam within 30 seconds and becomes a flexible, leathery substance over the course of several hours.
虽然早期曾变为金色背景下的黑色十字以及十字的边缘变化为锯齿状，但圣大卫之旗如今基本保持于黑色背景下的金色十字。
The flag of st David is a gold cross on a black background, although earlier variations exist.These include a black cross on a gold field and engrailed edges on the cross.
现在已有把二氧化碳变为合成气的工业生产，而且可以在同一个生产过程中继续把合成气转化为液态碳氢化学物。
Commercial processes are already available that use carbon dioxide to make a mixture called syngas, which can then be converted to liquid hydrocarbons in a process that can run continuously.
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