She brought with her three friends, none of _________ I had ever met before.
The origin of ____ life on earth is ____ question that interests astronomers.(原创)
---_______ they stop to have a rest? ---No, let them go on.
He was so lucky to ______ only a fine for such a serious mistake.
Even scientists cannot completely ________for the strange behaviors of the animals before an earthquake. (原创)
He is said _______ a new machine recently, but I don’t know when he will make it.