fter a ________ , the author went onwriting his novel. Which of the following cannot be put in the blank

Our English teacher is very ______ to us. We all love her.

No one can stop us from going there, ______?

Jack, this is the third time that you have been late this week．—Sorry, sir, but I was_____ for 15 minutes on the way here in the traffic jam．

I learned about elephants the day before yesterday. There are no bones in the back of their feet.-_______.