Помогите срочняяк

Образуйте страдательный залог:

1.Radio(invent)by Popov in Russia.

2.A new president (elect) every four years in the USA.
3.The books already (pack).

4.My clock (not repair) by George.

1.Radio was invented by Popov in Russia.

2.A new president is elected every four years in the USA.

3.The books have already been packed.

4.My clock was not repaired by George.