I was so tired that I could ______walk any farther.

---I can’t find my pen. ---___ you put it in your book.

English is          too difficult for me. I can't learn it well.

— Mr. Smith, would you please speak a little more __________?— Sorry! I thought you would follow me.

---Mr. Bill always makes his class very lively and interesting. --- You are right. No one teaches ____.