_______ in the storybook that he had bought not long before, the boy didn’t notice his mother go into his room.

The first textbooks _____ for teaching English as a foreign language came out in　the 16th century. 

________, you need to give all you have and try your best. 

I really appreciate ____ to help me with my maths, but I’m afraid that I have no time this week．

Several months later, he found his deskmate very difficult _______.