The unit tests at the base of the pyramid are important for several reasons.
在金字塔底部的单元测试很重要，这有几个理由。
2
The internal structure of silica has a pyramid(tetrahedron) unit.
硅的内部结构是一个四面体。
3
Samples of blended coal ash were taken from the boiler of a power plant 700mw unit. Their softening temperature was measured by a pyramid method on an intelligent ash-melting point measuring device.