单项选择题
A. Can I help you C. Safety belt, please. E. Is there anything serious G. What flight are you taking B. We are taking off at last. D. The engine went wrong. F. Just a moment, please. H. It should be OK in an hour.
A．building bridges across them B．driving generators into them C．building dams across them D．directing them into homes and factories
A．what makes people feel cool near a lake or an ocean in summer B．everything about the ocean C．why the ocean does not get more and more salty D．what happens to the salt in the ocean