The surfaces should be luted before they are clamped together and fastened.将表面夹在一起并紧固之前应该用封泥封住。Check that the bolts are secured, or an accident could result.检查螺栓是否紧固，不然可能会发生事故。She has invented a nifty little gadget for undoing stubborn nuts and bolts.她发明了一种灵巧的小工具，用来松开紧固的螺母和螺栓。