Affirmative:

Sudject + Verb + Compl.

• Tom studies at school every day
• Lucy writes at letter for his friend

Negative:

Subject + Aux.Verb(do/does) + Not + Verb + Compl.

• We do not estudy english
• Lucy doesn't write a letter for his friend

Interrogative:

Yes/No Question

Aux.Verb + Subject + Verb. + Compl.?

• Does tom study at school everyday? 

      Yes: -Tom does

              -Tom studies at school

              -He does 

      No: -Tom doesn't

             -He doesn't

             -Tom doesn't study at school

Inf. Question

W.H + Aux.Verb + Subject + Compl.?

• What do we study?
• Where does tom study every day? 
• When does lucy estudy at school?