You have to keep alert when you are in the supermarket; otherwise, you might _____ what you actually don’t need at all.
Old as the car is, _____ it works quite well.
The stubborn boy didn't _____ so that he missed the chance.
You'd better make a mark _____ you have any questions.
I like ______ of the two stories, for this story is _____ than that one.
Our English teacher _____ by the teachers and students.