用be sure ,be not sure,are you sure...be sure of的相应形式填空
1.i________________the pool is open until 6:00 2.i 'll take the blue one .___________?yes i________ 3.are you sure you know to get there?no i________ 4.mr green _______________if he ll be able to came 5.if you re not ____________the answer,you can ask the teacher