A．was a known fact in Bacon’s time
B．is verified by maggots in putrid flesh
C．is more apparent than real
D．is a speculation which has no basis in observation

A．new radio devices should be developed for tracking the endangered blue whales
B．blue whales are no longer endangered with the use of the new listening system
C．opinions differ as to whether civilian scientists should be allowed to use military technology
D．military technology has great potential in civilian use