I don’t allow you ________ so high a mountain.
| A．to risk going | B．risking to go | C．going to risk | D．risk going |
_________ many times, he finally understood it.
| A．Told | B．Telling | C．Having told | D．Having been told |
The chairman thought _________ necessary to invite Professor Smith to speak at the meeting.
| A．that | B．it | C．this | D．him |
It was not until nearly a month later _________I received the managers reply.
| A．since | B．when | C．as | D．that |
---- What do you think of the book?
---- Oh, excellent .It is worth __________ a second time.
| A．to read | B．to be read | C．reading | D．being read |
Such animals like dinosaurs died out because they could not _________ to the change of the climate.
| A．suit | B．keep | C．adapt | D．switch |