ballast|ballasts

他的幽默感在压力时期起到了稳定作用。

His sense of humor served as ___ballast during stressful times.

工人们正在为铁路路基铺设新的道砟。

The workers are laying new ___ballasts for the railroad foundation.

工人们在船底装载石块以压舱保持平衡。

Workers loaded stones in the hull to ___ballast the ship for stability.