WITH WHAT TOPIC IS THE PASSAGE PRIMARILY CONVERNED

56. - DE THI THU DH THAN KHAO CO DAP AN
Tiếng Anh DE THI THU DH THAN KHAO CO DAP AN
56. With what topic is the passage primarily converned?A. Communication among drivers. B. Direct observation of the ocean floor.C. Technological advances in oceanography. D. Undersea vehicles.