单项选择题
A．the auctioneer knocks the buyer down B．the auctioneer knocks the rostrum down C．the goods are knocked down on to the table D．the auctioneer bangs the table with a hammer
A．for the highest price offered B．only at fixed prices C．at a price less than their true value D．very cheaply
A．take care not to be over-critical in his writing B．watch carefully to see that nobody else takes his job C．be careful to ensure that his comments retain their value D．be sure that his salary keeps pace with inflation