French is _______ difficult to learn.

We can see no clouds in the sky. Therefore, there’s no doubt ______ it will be fine tomorrow.

Must we keep the window _______ all the time? —No, you don’t have to.

What about the popcorn?—Wonderful! Nothing tastes ________.

Did you get your report card today, Susan? — Yes, I did. I didn’t do well in science. Because it’s too _______.