Parodontal
a. 牙齒周圍的, 齒根膜的
??? 情景例句
Radiation exposure can damage your genes and make them vulnerable to mutation.
輻射會破壞你的基因組織，使它們突變。
I asked him to keep quiet, but he wouldn't.
我請他保持肅靜，但是他不肯。
The moon travels round the earth.
月球繞著地球運行。