1. All living organisms, regardless of their unique identity, have certain biological, chemical, and physical characteristics in common.
    A) as a result of
    B) considering
    C) on purpose
    D) whatever
    2. The most pressing problem any economic system faces is how to use its scarce resources.
    A) puzzling
    B) difficult
    C)terrifying
    D) urgent
    答案：D　　D