我把钥匙放在桌子上，你能帮我拿一下吗？

I left the keys on the table, can you pass ___them to me?

今天外面很冷。

___It is very cold outside today.

是谁在打电话？肯定是妈妈。

Who is calling? ___It must be mom.

是我弟弟弄丢了钥匙，不是我。

___It was my brother who lost the keys, not me.