In metalwork one advantage of adhesive-bonding over spot-welding is that the contact, and hence the bonding, is effected continuously over a broad surface instead of a series of regularly spaced points with no bonding in between. 全句结构为 one advantage is that +从句(主语the contact)+插入语(and hence the bonding)+is affected over a surface instead of points 确保平行,points前要有介词 (D) rather than at 有介词at保持平行,并且符合逻辑意思。 |