36().

A．To look back to the early days of this passage.
B．To explain what technical problems may occur with computers.
C．To discourage unnecessary investment in computers.
D．To warn against a mentally lazy attitude towards computers.

A．life on land probably began about 430 years ago
B．the first animal on land came from oceans
C．there wouldn’t be animals without plants
D．plants are the only form of life that is able to get and store energy