圆度仪原理:mind your head 是什么意思？

mind your head 是什么意思？ keep your head down是什么意思 Dont hang your head in sorrow是什么意思？ Love can make what you set your mind to是什么意思？ at / in the back of your mind 是什么意思 use your head TURN AROUND YOUR HEAD!~ work with your mind OPEN YOUR MIND ? teachers have eyes in the back of their head、in over your head、all ears这些习语是什么意思？