Переделать предложения в отрицательную форму
а1. We usually watch TV on Sundays.
a2. We usually are watching video on Sundays at 16:30.
a3. We have watched video on Sundays since 2003.
a4. We have been watching video since 12:30.
b1. We watched TV on Sundays.
b2. We were watching video on Sundays at 16:30.
b3. We had watched video on Sundays till 2003.
b4. We had been watching video for two hours when she came.
c1. We shall watch TV on Sundays.
c2. We shall be watching video on Sundays at 16:30.
c3. We shall have watched video on Sundays by 19:00.
c4. We shall have been watching video for two hours when she comes.