单项选择题
A．most of the world's oil supplies. B．2/3 of the world's oil supplies. C．1/3 of the world's oil supplies. D．1/4 of the world's oil supplies.
A．In the end of the ninetieth century. B．In the early twentieth century. C．In the early nineteenth century. D．At the end of ninetieth century.
A．Weren't B．Had it not been C．Hadn't it been D．Had it been not