变色牙齿

disclosing agent───n.牙菌斑显示剂

disclosing agents───披露代理人

discoloring───v.（使）变色，褪色，损坏……的色彩（discolor的现在分词）

discolorment───n.变色；污染

discolouring───v.使变色；使褪色（discolour的现在分词）

discounting rate───贴现率；折现率

like pulling teeth───极端地困难

My childs teeth DID get a slight greyish tint to them. However, the discoloring went COMPLETELY away within 2 weeks after stopping the Fer-In-Sol.───孩子的牙齿在那个阶段有轻微的灰色，但是停药后2周就完全恢复了。