1.go hand in hand 紧密联系；息息相关
For us, research and teaching go hand in hand.
对于我们来说，研究与教学密切相关。

2.narrow a gap 缩小差距
Actually it gotta take a very very long time to narrow the gap between urban people and rural people and to balance the problem.
事实上，平衡这个问题、缩小城乡差距要花很长很长的时间。

3.crack jokes 讲笑话
This doesn't mean that you have to crack jokes or entertain us, but just being able to laugh at yourself is enough.
这并不意味着说你一定要开玩笑或者娱乐我们，只要敢于笑笑自己就足够了。