她完全理解量子力学的复杂原理。

She thoroughly ___understands the complex principles of quantum mechanics.

她很快就理解了老师讲的数学概念。

She quickly ___understands the math concept explained by the teacher.

她完全理解我失去宠物后的悲伤。

She fully ___understands my sadness after losing my pet.

法官将这条规则理解为企业必须履行的义务。

The judge ___understands this rule as an obligation companies must fulfill.