英语翻译高中英语语法解释加翻译------ once every two years,whether it is a c

whether it is a car,a bus or a lorry作为插入语,is the rule that all drivers must obey in our country.是句子的谓语部分和宾语部分,整个句子缺主语,动名词作主语,所以 Being examined
作主语,examined不能作主语
整个句子的必要成分是Being examined is the rule,其他都是修饰成分