--- Where did you meet him for the first time?
--- Maybe it is in the museum ______ we listened to the lecture ______ we got to know each other.

We work together to achieve our common purpose： ______ world that is safer, cleaner and healthier than______ one we found．

  At the United Nations Climate Change Conference, the UN Secretary General points out that, ______, the climate situation will get worse and worse.

---Tom was late for class this morning again.
---You know, _______.

You didn’t take his advice. ____ his advice, you _____ such a mistake.