单项选择题
A．people feel cool when they are near a lake or an ocean B．scientists can explain everything we want to know C．scientists can explain many things but not everything D．the salt in the ocean comes from rocks
A．To recognize worthwhile contributions to humanity. B．To resolve political differences. C．To honor the inventor of dynamite. D．To spend money.
A．fewer people moved from countryside to the cities B．more people moved from countryside to the cities C．industry developed less fast D．many people moved to the cities without the development of industry