一When did you buy this still life picture?一It was in 1999 I traveled in Paris.
_________ many times, he finally understood it.
The chairman thought _________ necessary to invite Professor Smith to speak at the meeting.
It was not until nearly a month later _________I received the managers reply.
---- What do you think of the book? ---- Oh, excellent .It is worth __________ a second time.
Such animals like dinosaurs died out because they could not _________ to the change of the climate.