Prépare ta conversation téléphonique avec M. Stanley. Écris quatre phrases affirmatives expliquant ce que tu as déjà fait. Écris trois autres phrases négatives pour lui expliquer ce que tu n'as pas encore fait. Utilise le Present Perfect.)

the direction of the magnetic field produced by an electric current will change when the direction of the electric current changes. for example : if a current is flowing in a straight length of wire, the magnetic field is described by a concentric circle (using right-hand rule).

sentence lenght varies according to word choice.you select which word to use and that will require to use other expressions that collocate with the word chosen.sentence length will vary   according to the choice of words you make to express your ideas.  

you didn't finish the sentence , how am i gonna you if you didn't finish the sentence

the novel is told in flashback