The problem was very difficult to handle．We worked it out，__________ ．

(2013·江苏，27)“Never for a second，”the boy says，“________that my father would come to my rescue.”

Thanks for________ me to go to your Englishparty.

Three free tickets for the Expo will be given to ________ comes first in the competition

I tried to call you last night, but Icouldn’t ______.