а) I wish he were not so light-minded. b) I wish he were more serious.
a) Now I wish I had listened to his advice (had followed his advice). b) Now I wish I had not followed his advice.
a) I wish you had not come so late. b) I wish you had come earlier.
a) I wish we had not gone before he came. b) I wish we had waited till he came.
a) I wish they knew it already. b) I wish they did not know about it.