A. concerned with the problems that we will have to solve in the future
B. reading books of science fiction
C. political implication (涵义)
D. a recurrent theme
E. read worldwide People enjoy______

A．to make some sound experiments in the oceans
B．to collect samples of sea plants and animals
C．to estimate the length of cable that was to be made
D．to measure the depths of two oceans

A．but
B．although
C．and
D．despite