It started to rain.We coulf not keep on cleaning the beach (because)

1.We go by plane.It will be quicker( conditional sentences type 1)
2. It started to rain.We coulf not keep on cleaning the beach( because)
3.saving energy conserve the Earth's resources.Saving energy helps to protect the environment ( and)
4. The oil will pollute the sea. People are worried ( that- clause)