I followed the man in a blue jacket thirty meters ______ me and watched him enter the hall

People are _________the use of alternative energy sources. Because the fossil fuels _________will be used sooner or later.

In order to _____ the rising production costs, the subscription rates have been increased.

This problem seems so ______ that no one can work it out ______.

Usually, a mother wolf gives birth to five to seven baby wolves .