PDF chapter test TRY NOW

1. David used ECO2 for carrying out __________.
   
 
2. It became a part of routine for David to use __________ for his everyday activities.
    
 
3. David had also begun to use ECO2 to speak using __________ sentences.
   
 
4. David seems to be a more confident and __________ as a result of using ECO2.