Once we have________some knowledge, things do not become more difficult, but comprehensible.
1 haven't got a single ______from Aunt Mary since I last saw her.
The rescue team ______to help but failed to get there in time.
--Will you two go to the show tomorrow? ---No. We're going to a lecture, or at least I'm planning ____.
I'd love ___ to your party last Sunday if not because of the unexpected guests.
.____ the temperature falling so rapidly, we couldn't go on with the experience.