---Be careful. You might fall into the river.

---Thank you. I ________ I ________ so close to it．

A．didn’t know; am standing

B．don’t know; am standing

C．didn’t know; was standing

D．didn’t know; would standing

雷电灾害是联合国国际减灾委员会公布的最严重的（）种自然灾害之一，也是《中华人民共和国气象法》中所涉及的（）种自然灾害之一。