Present simple

Today we're going to learn how we form and use the present simple.

http://learnenglishteens.britishcouncil.org/grammar-vocabulary/grammar-videos/present-simple

• We use the present simple to talk about repeated actions or events, permanent states or things which are always true.
• Permanent states are situations or feelings which are not temporary.
• We also use the present simple for general facts, for example when talking about science or geography.
• The third person singular forms end in-s or -es. (He, She, It)
• For negatives we use the subject + do/does + not + infinitive without to 
• For most verbs we use the present simple of the verb do/does + subject +infinitive without to to form questions.

Here there are some exercises to practice the present simple:
http://www.agendaweb.org/verbs/present-simple/index.html
http://www.agendaweb.org/exercises/verbs/present-negative
http://www.agendaweb.org/verbs/present-simple-interrogative-exercises.html