Grammar Reference
The present simple is used to talk about habits and facts - things that are often permanent.
The present continuous is used to talk about changing situations and developments - things that are often temporary.
  Affirmative and negative
| 
       I  | 
    
       am  | 
    
       (not) studying  | 
    
       Japanese at night school.  | 
  
| 
       You/we/they  | 
    
       are  | 
  ||
| 
       He/she/it  | 
    
       is  | 
  
  Question
| 
       Am  | 
    
       I  | 
    
       studying  | 
    
       Japanese at night school?  | 
  
| 
       Are  | 
    
       you/we/they  | 
  ||
| 
       Is  | 
    
       he/she/it  |