Something is wrong with the window; it _______ not open.

—How’s your tour around the North Lake? Is it beautiful?—It          be, but it is now heavily polluted.

I ____ you, but I didn’t think you would listen to me.

If Alice ______this afternoon, the meeting should be put off.

—This wall of air is an effective answer to the problem  and it ____ work.  —But it is a question to put such a wall of air around the statue.