-ING FORM (Examples: going, speaking)

Used in many kinds of sentence. After some verbs:

like                                                                                 I like speaking Arabic
love                                                                                I love going to the beach
hate                                                                                I hate waiting for people

And after all prepositions:

before                                                                           Before going to bed I usually clean my teeth
after                                                                              After seeing the doctor she felt better
for                                                                                Thank you for inviting me
at                                                                                  He's good at playing football
without                                                                        Can you live without eating?

And in the present continuous tense:
                    What are you doing?  'I'm reading the article'