Rice husks form small cases around edible kernels of rice and are rich in silicon dioxide, an essential ingredient in concrete.
包裹米粒的米糠皮富含二氧化硅，而二氧化硅是混凝土的必要成分。
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"Without concrete and desirable goals, a budget is just drudgery," Rich said.
没有稳固和满意的目标，预算就会成为一件苦差事。
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This week rich and poor countries agreed on guidelines for releasing aid to save forests, in the first concrete sign of global action on climate change since Copenhagen.