含碳量在0.25%~0.5%范围内,通过淬火及高温回火可获得良好的综合力学性能的这类钢,叫()。
A、渗碳钢;
B、调质钢;
C、弹簧钢;
D、都不对。
参考答案:B
大叶性肺炎患者如能听到胸膜摩擦音,该摩擦音的特点为()
A.仅能在吸气时听到
B.吸气初明显
C.呼气初明显
D.与心搏一致
E.屏气时不消失
We are writing to the manager ______ the repairs recently carried out at the above address.
A.with the exception of
B.with the purpose of
C.with reference to
D.with a view to