But the robotics part is the hardest part. That's the old brain. That's really hard.

Hard

The hardest part still lies ahead the miniaturization needed to fit a nuclear device into a warhead.

The task is daunting.

Sophisticated System

The situation is complicated.

Graphics

Extra difficult.

Tough thing to do.

Despite the fact that this is the most complex and diverse system in the universe, there's an extraordinary simplicity being expressed by this.

This is a tricky business.

Those are really tough.

So, yeah, so this is again difficult.

This is a daunting task.

It is a difficult problem.

A computer is a complex machine.

Is it difficult work?

This is a difficult situation.

The structure of the brain is complicated.

The surgery is quite difficult.

Grammar is very complicated.

It's a complicated story.

This is a difficult job.

This is a difficult mission.

It's a difficult job.

This book is difficult.

This is the difficult part.

The situation is very difficult.

It's really difficult.

Sophisticated communications sweep.

So, yeah, so this is, again, difficult.

It's a big task.

You see a lot more structure there.

Now the tricky part.

A car is a complex system.

There's the challenge.

Iran is an extraordinarily complex country.

The history is complicated.

It was not an easy game. It was complicated.

The brain is just a complicated machine.

It s a very complicated situation.

That is a very complex machine.

Grammar is a very complex thing.

The problem was difficult to solve.

It's a very complicated situation.