[originaltext]　　(3) US President Barack Obama is urging the public to persuade

　　(3) US President Barack Obama is urging the public to persuade members of Congress to extend a payroll tax cut that saved a typical middle class family about $ 1 000 last year. The tax cut is set to expire on December 31.
　　(4)Obama’s message during his weekly address Saturday comes a day after Americans got news of a drop in the unemployment rate and the creation of 120 000 private sector jobs last month. The US leader says extending the payroll tax cut would help build on those positive trends. Obama says Congress should not go home for the holidays until legislators extend the payroll tax. He appealed to the public to get the message over to lawmakers.
　　3. Why is Barack Obama urging to extend a payroll tax cut?
　　4. When did Barack Obama announce his urge to extend payroll tax cut?