19. It’s quite an informal gathering ; you needn’t ______for it .
---Sorry, madam, you can’t get on the train. This is _____ old ticket. ---Oh! It’s out of _____ date.
The _____look on Sam’s face suggested that there must have been something _____ on his way to school.
Walking is a good way to keep fit. _______, swimming is helpful for your health.
The president spoke at the business meeting for nearly an hour without _____ his notes.
Seeing the ______ of children playing together on the beach, I felt so happy.