Tips to Remember Grammar

The Simple Present and the Simple Past Tense

 These Tenses are so very simple they do not use a helping verb ,they manage with their own verb.

                 So,do not use the helping verbs,'is' ,'are','was','were'.

                    ie.The cat drinks milk.

The Present Continuous and the Past Continuous
 
These Tenses  need a helping verb,so,use the helping verbs,'is,are,was,were,along with the 'ing' form of the verb.
                     ie.The cat is drinking milk. 
 

The Perfect Tenses
 All Perfect Tenses use the helping verb 'has,have and had' along with the 'Past Participle' form of the verb.

The Perfect Tense is very possessive of his helping verb,so,use the helping verbs,'has,have and had' only with the Perfect Tense.

                  ie.The cat has drunk milk.

 The Passive Voice

Be careful to check the 'Tense' of the 'Action Verb' when changing from 'Active to Passive',and then decide on the 'Helping Verb' according to the 'Tense'.
                    ie. The cat drinks milk.
                         Milk is drunk by the cat.

Be careful to check the 'Tense' of the 'Helping Verb' when changing from 'Passive to Active',and then decide on the 'Tense 'of the 'Action Verb'.
                     ie.Milk was drunk by the cat.
                         The cat drank milk.

                           A Kind Warning

                        Read your questions carefully before attempting.

                                   Best wishes for your examination.