以下哪一项不属于电动助力转向机构的布置方案（）。
A.转向轴助力
B.齿轮助力式
C.转向盘助力式
D.齿条助力式
参考答案：C
They put forward a lot of plans at the meeting, none of _______ were carried out in their work.
A．which
B．them
C．what
D．that
为显示肝内高密度转移灶，窗宽的设置是（）
A.约在100～250HU
B.约在0～350HU
C.约在250～450HU
D.约在-50～150HU
E.约在200～500HU
