沈阳二手机床市场:how should是什么意思?

how should是什么意思? how should history be taught? How many mobile specifics should be suitable? How should medical service in Beijingbe improved? How long should your legs be? How long should your leg be? How long should your leg be? How should study the scientific cultural knowledge? how是什么意思 should在这是什么意思?