He had a sudden sinking feeling in the pit of his stomach.
他内心深处突然有一种不祥之感。
This text introduced the practice method of the box permanent steel petroleum derrick shaft sinking in the construction of vertical shaft pit shaft.
在立井井筒建设中，我们在原设计的基础上，对箱形永久钢井架凿井的实际方法作了改进。
This text introduced the practice method of the box permanent steel petroleum derrick shaft sinking in the construction of vertical shaft pit shaft.
在立井井筒建设中，我们在原设计的基础上，对箱形永久钢井架凿井的实际方法作了改进。
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