It’s _____ hard problem for the twins that ____ of them can work it out.

We found impossible to finish the work in such a short time.

Which of the two cameras are you going to buy?—I’ll buyof them，so I can give one to my friend．

Hi, Nancy. Shall we go to France for the long holiday?— Sorry, Kate and I ______ there twice.

Tom isn’t good _____ other kids. So he is lonely(孤独的). [ ]