单项选择题
A．water pollution B．air pollution C．noise pollution D．rubbish
A．because the earth is being polluted day and night B．thanks to science development C．because of the rise in population D．because the earth is blown away by the wind every years
A．are trying activities such as bungee jumping B．are climbing the highest mountains C．are coming chose to death in sports D．are looking for adventures such as exploring unknown