根据句意及提示写单词。
The train moved at high _____________(速度).
How to protect the ________________(环境)has been under discussion.
A sparrow was ______________(死). Let’s bury(埋) it under the tree.
Last weekend, my father bought a __________(两件,几件事物) of beautiful key rings for me.
We all love Liu Qian’s ________________(魔术).