It’s a bad habit to leave the work ______.
| A．undo | B．undone | C．undoing | D．done |
When you get on stage for the first time, you may be surprised by ______bright the lights are.
| A．what | B．so | C．how | D．too |
If you had joined the chat room ten minutes ago, you ______what we were talking about!
| A．have known | B．knew | C．would have known | D．would know |
Yesterday, when I went to his office, he ______ online for some information. I think it will be an interesting lecture.
| A．searched | B．was searching | C．would search | D．has searched |
Instead of telling the joke he _______, Crystal made up a new one.
| A．made | B．has made | C．had made | D．would make |
I am pleased to have this chance today ______to you about the United Nations or the UN.
| A．talking | B．to talk | C．talked | D．talk |