what was happening 和what was happen
I had a mistaken view of what was happening.
我对于所发生事情的看法是错误的。
The Ministry of Foreign Affairs speaker explained what was happening in Hongkong in detail, which clearly showed China's firm attitude.
外交部发言人详细解释了香港发生的事情，表明了中方的坚定态度。
We had no idea what was happening.
我们不知道正在发生什么