单项选择题
A．nobody will try to get them B．they can become very valuable C．everybody would like to buy them D．they will be worthless
A．Credit cards have more advantages than travellers’ cheques. B．Dollar bills are as convenient as credit cards. C．One-cent coins have been withdrawn from circulation. D．You can increase your credit limit as you lik
A．5 per cent of the world’s water B．15 percent of the world’s water C．20 percent of the world’s water D．50 percent of the world’s water