Perhaps the day will come ____ people will be able to breathe clean air in cities．
| A．when | B．while | C．as | D．since |
He was disappointed to find his suggestion_______.
| A．turning down | B．turned down | C．to be turned down | D．to turn down |
The salesman scolded the girl caught ______and let her off.
| A．to have stolen | B．to be stealing | C．to steal | D．stealing |
It was so cold that they kept the fire ________all night.
| A．to burn | B．burn | C．burning | D．burned |
Believe it or not, he was seen ______upstairs just now.
| A．to go | B．to going | C．having gone | D．go |
They knew her very well. They had seen her ____up from childhood.
| A．grow | B．grew | C．was growing | D．to grow |