Tā zài shuǐní qiáng lǐ dǎle sì kē péngzhàng luósī.
He drove four expansion bolts into the concrete wall.
Tips
usage
A 膨胀螺丝 is a metal anchor whose sleeve expands inside a concrete or brick wall when you tighten the screw, gripping the surrounding material. For drywall (less common in Chinese homes), people use 塑料膨胀管 (plastic wall plugs) instead.
