单项选择题
A．birds and parasites B．birds and sheep C．parasites and sheep D．sheep, birds and parasites
A．a new way of buying furniture B．a new way of moving from place to place C．why some people rent their furniture D．how some people rent their furniture
A．helped develop the creativity of a scientist B．kept a rare gift for a scientist C．prevented a scientist from thinking freely D．contributed a lot to science and technology