Mary failed the driving test again. If she ______ harder, she ______ the test easily.
She is not used to __________ like that.
The new rule has been working effectively since it __________.
As a result, these endangered animals may even __________.
__________ time goes on, our country becomes more and more powerful.
The newly discovered star was named __________ a Chinese astronomer __________ honor of his contributions to astronomy.