SIGNALS: environmental stories for Europe

Complete the gaps:

1.-When his mother was a .......... there were more butterflies
2.-There was also .......... rain
3.- But in the ................... half of ................. butterflies have disappeared
4.-Strange ........... like this send us signs about the state of our .......................
5.-Using signals such as levels of air pollution, the ...................... water or the number of ...............