There were lots of smooth flat stones of differing sizes and colours.

对有不同大小及颜色的石头光滑平坦地段。

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To produce a sample proof: Lay the substrate out on a smooth flat surface.

要产生一个样本证明：躺着的基板，光洁平整的表面上。

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The heat transfer data of nucleate pool boiling on a smooth flat surface were measured in HC170/HFC23 system.

实验测量了新型共沸混合工质HC170/HFC23的池核沸腾传热特性。

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Railroad companies employed thousands of workers to create the smooth,flat pathways required by trains.

VOA: special.2009.02.21

Blurred footprints, a smooth flat stone good for skimming.

NEWYORKER: Getting Closer

Over the centuries, the river had slowly carried away mountainsides, tumbling and cracking rock, reducing boulders into a rainbow of smooth, flat stones the size of a child's hand.

CNN: The seven stones of simpler living

The plastic must also be flat and smooth for the reading to be accurate, and the object must be brought to the machine (which is not very portable) for analysis, which takes yet more time.

ECONOMIST: Recycling