重点讲解：
1. give out
公开，宣布（消息等）；
eg. How often do you give your phone number out?
你经常把自己的电话告诉别人吗？
eg. He wouldn't give out any information.
他不愿透露任何消息。
2. pay back
偿还；回报；
eg. I am indebted to my friends and families and wish I could pay them back.
我深深的感谢我的朋友和家人并希望能够回报他们。
eg. I've no idea how I can pay you back for all your help.
我不知道怎样才能报答你对我所有的帮助。
3. melt down
熔化，熔毁（以再利用）；
eg. Some thieves do not even bother to melt down stolen silver for its scrap value.
有的小偷懒得为了一点蝇头小利去费劲把偷来的银器熔掉。
eg. This programme investigates the rate and extent of the melt down in some of the remotest regions on Earth from Alaska to Antarctica.
本节目前往地球最偏远的地方，从阿拉斯加到南极洲，探索冰河融化的速度和范围。
