It was not until all the fish in the pond died that________ the situation was serious.
| A．did he realize | B．he realized |
| C．he had realized | D．had he realized |
I found ______ possible to answer all the questions within the given time.
| A．that | B．it | C．this | D．what |
——Have you any money on you? I need some badly.
——Sorry, but ______ at all .
| A．not | B．nothing | C．none | D．quite a little |
Some tourists think that the beauty of mountains is greater than ______ of deserts.
| A．one | B．those | C．the one | D．that |
We've got two TV sets, but we still can't watch anything because ______ works properly.
| A．neither | B．either | C．each | D．none |
--- Did you find the pen yesterday?
--- No, I didn’t find ________, but I have bought ________.
| A．it; it | B．one; it | C．it; one | D．one; one |