For questions 1-8, read the text below and decide which answer (А, В, C or D) best fits each gap. There is an example at the beginning (0).
Planes can make it rain
The scientists looked at satellite 3 of clouds above airports, and also studied computer models of the way clouds behave. What they found was that as a plane flies through a very cold cloud, the air behind it expands and then cools 4 rapidly. This sudden drop in temperature, 5 with the hole formed in the cloud where the plane has passed through, can increase the 6 of rain or snow on the ground.
In the case of major airports, with hundreds of flights every day, this can have a significant 7 on weather patterns up to 100 kilometres away. The researchers point out, however, that aircraft passing through clouds are 8 to affect the global climate.