使用牙刷去除牙垢很有帮助.The use of a toothbrush to keep tartar down is very helpful.除牙垢用带尖工具除去牙齿表面的 ( 污垢 )To remove ( tartar ) from tooth surfaces with a pointed instrument.我的牙齿上有许多牙垢.I have a lot of tartar on my teeth....
Such was the ideal; the occasional conflicts were due to human imperfection.这样的分工是完美的, 偶尔的冲突是人类的缺点所致.The imperfection of language makes some ideas hard to express.语言功能的不完善使一些思想难于表达.The noble science of Geology loses glor...