Fill in each blank with a suitable preposition or particle.
17. We made........................that they had forgotten Jane’s birthday, though it was not true.
18. There was tremendous excitement in the streets and the shouting didn’t die....................till after
midnight.
19. A new organization is being set.......................for those concerned about the welfare of dolphins.
20. My father is going to go.....................the wall when he finds out that I’ve lost the keys.