Задание 3. Отметьте грамматически правильный вариант из данных в скобках. В одном из случаев верны обе глагольные формы.

1. I can't afford to buy such an expensive mobile. 2. Susan started running/to run when she was fourteen. 3. David kept collecting match boxes for many years. 4. They hope to arrive at the airport on time. 5. I don't object to signing these documents. 6. We refuse to join the party.