举例说明什么叫机械？

—Did you go to the museum to visit the photos on display yesterday?
— No. I didn't go there ____ the rain.

根据句意及首字母提示完成单词。
Mrs. Hand’s kid is only eight m____ old.
Today is my sister’s birthday, so I want to have a p____ for her
When is our English speech c____ ?
Ms King is Peter’s m ____  teacher. She sings very well.
——What’s the d____  today? ——It’s February 25th.

用化学用语填空
⑴常用于人工降雨的物质____。
⑵2个硫酸根离子____ 。
⑶金刚石____。
⑷写出过氧化氢的化学式并标出氧元素的化合价____ 。