Ellen was a painter of birds and nature, _____, for some reason, had withdrawn from all human society.
Bitten twice, the postman refused to ______ our letters unless we changed our dog.
______ to go abroad alone is what worries me most.
When I said someone was stupid, I didn’t ______ you.
Those who are not ______ with the progress they have made will have greater success.
Peter was so excited ______ he received an invitation from his friend to visit Chongqing.