The most (crucial) problem any economic system faces is how to use its scarce resources.

A:puzzling B:difficult C:terrifying D:urgent

Firewood is scarce in many parts of the world.（　）

A:hard to sell B:easy to make C:hard to find D:easy to store

Firewood is {{U}}scarce{{/U}} in many parts of the world.

A:hard to sell B:easy to make C:hard to find D:easy to store

The most {{U}}pressing{{/U}} problem any economic system faces is how to use its scarce resources.

A:puzzling B:controversial C:terrifying D:urgent

The most {{U}}crucial{{/U}} problem any economic system faces is how to use its scarce resources.

A:puzzling B:difficult C:terrifying D:urgent

The most crucial problem any economic system faces is how to use its scarce resources.

A:puzzling B:difficult C:terrifying D:urgent

The most {{U}}crucial{{/U}} problem any economic system faces is how to use its scarce resources.

A:puzzling B:difficult C:terrifying D:urgent

The most {{U}}crucial{{/U}} problem any economic system faces is how to use its scarce resources.

A:puzzling B:difficult C:terrifying D:urgent