—You don't seem to be quite yourself today. What's wrong?—Oh, I'm suffering from a cold. Nothing serious,______

He is quite sure that it’s____impossible for him to finish the task within two days.

It is _____that he has been addicted to the drugs and has difficulty quitting it.

I cannot thank you ______ much of your kindness. I owe my success to you.

It was raining heavily. Little Mary felt cold, so she stood ___to her mother.