Иногда изображение на экране телевизора двоится. Что заставляет электронный луч писать второе изображение?

1) This information is available to all.

2) He
contributes an article to a newspaper every week

3) This
company was established in the last month

4) Kate was qualified as  a skilled secretary

5) Enemy's
troops were  trying  to destroy the city and capture soldiers and take them
prisoner

6) Commander
in chief arrived in headquarters in the evening, he was wounded during
hostilities and his friend fell on the battlefield 

7) Officers
study the means of carrying out modern warfare