我要做的就是，选择一块够硬的石锤，这次我选这块是个头有板球大小的石英岩卵石。先挑个地方锤下去，接着我就开始从这地方开始凿了。

And what I do is, I select a hard stone hammer, in this case a quartzite pebble about the size of a cricket ball, and I elect to hit it in one place - and this is where I start to knap.

youdao

本文主要介绍粗粒级手选废石、冶炼炉渣及二者按不同比例混合料的压缩性能测定方法。

The compression property test method of coarse fraction hand sorting waste rock, smelter slag and their mixed filling materials had been introduced in this paper.

youdao

本文从白石水库泥沙模型试验入手，模型试验首先通过模型糙率和模型选沙验证试验，说明模型制作和选沙是合理的。

Letterpress starting with the former of the experiment for bedload. Firstly, we account for the former made and the sand selected are reasonable by experiments.

youdao