1.   a person at the door.  

2.   no one at the door. 

3.   twenty eight students in my English class. 

4.   only one English class. 

5.   three French teachers. 

6.   some juice in the refrigerator. 

7.   over twenty centimeters of snow on the ground. 

8.   many things to do. 

9.   very good restaurants in my town. 

10.   just one Chinese restaurant though.