It __ sometimes said that animals can use language.

They certainly do communicate with ___ another in very sophisticated ways.

Many animal species talk to ____ other using a wide variety of sounds and calls.

However, animal sounds, such __ barks and calls, tend to be a reaction to what is happening in their environment.

In contrast to animals, humans are also _______ (ABLE) of communicating about past or future events.

In some experiments, chimpanzees have ____ taught how to communicate using their hands.

Some animals have been taught to combine signs in _____ to make simple sentences.

It takes a huge ______ of training for animals to form complete sentences.

For me, cycling up hills is almost __________ (POSSIBLE) difficult.

I find it __________ (EXHAUST) to cycle long distances.