n.操练,钻头,军事训练,(应对紧急情况的)演习
vt.& vi.钻(孔),打(眼),操练,训练
vt.作…演习,操练
It took five years to drill down to bedrock.
耗时五年才钻到了基岩。
A plug had been inserted in the drill hole.
钻孔已塞上了塞子。
The drill should be slowly rotated to ensure a clean hole.
钻头必须缓慢转动,以保证钻孔平整光滑。