compulsory: a.强制性的
coverage: n.承保范围
expiration: n.期满；截止
insurance: n.保险
insurer: n.保险公司
personal liability: 个人责任险
policy: n. 保单
policyholder: n.投保人
premium: n.保险费
renew: v.更新；续(约)
rider: n.附加条款
waiver: n.免责险