A． It being a fine day B. The day was fine C. It was a fine day D. Being a fine day
单项选择题With the population explosion, scientists will have to（）new methods of increasing the world's food supply.
A．come up with B．carry out C．lead to D．stick to
单项选择题Businessmen make most of their income from profit（）by producing and selling products.
A．earning B．is earned C．earn D．earned
