所有分界面将能反射或散声波到达某个程度，包括龟裂、内容物、砂眼分布范围、及其它裂痕。

All interfaces will reflect or scatter waves to some degree. This includes cracks, inclusions, grain boundaries and other discontinuities.

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试验后取出试样，检视试样表面是否产生龟裂、裂痕。

Finally, take out of specimen for checking whether its surface has crack or fissure or not.

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