Trace element mixes serve as insurances.微量元素只是作为一种保障措施.First of all, some doctors don't participate in some insurances by definition.首先, 一些医生 肯定 不会参加某些保险.These five kinds of insurances all exist the certain problem....
他天生擅长交际：他的祖先曾是封建领主。Diplomacy was in his blood: his ancestors had been feudal lords.许多人留恋不舍地回顾封建时代.Many people look back with nostalgia to feudal times.他是封建领主.He was a feudal lord....