THREE POINTS OF GRAMMAR THAT I HAVE PROBLEMS

• First on the prepositions, because I think that I don´t know as many as I should know
• Many times happends me that I forget the structure of a sentence by the name, for example If my teacher ask me to write a sentence with the present perfect continuos I´m going to think...., but if the teacher give me an example that is going to be easy for me.
• Other problem is with two words are mixed and together has a completely different meaning , I don´t remember the name, those are easier for example pick up, turn off, but exist other much more complicated and I have trouble with that

MAGDALENA ORTIZ, CLASS 7 TO 9 PM