Поставьте во все времена британского глагола предложение I buy a now

Дополнительно кому не трудно вопросительное отрицательное положительное и общий вопрос

Present Simple - buy       every Sunday
Past Simple       bought   last Sunday
Future Sunday   shall buy   next Sunday
Present Continuous  am buying    now
Past Cont.         was buying       at 3 yesterday
Future Cont. shall be buying       at 5 tomorrow
Present Perfect   have already bought
Past Perfect     When she met me I had already bought a new dress
Future Perfect   I shall have bought a new dress by tomorrow morning
Present Perfect Continuous   have been buying         for an hour
Past Perfect Cont.  When she met me I had already been buying a new dress for an hour
Future             When you come I shall have been buying a new dress for an hour