【判断题】随着钢轨中含碳量的增加,在室温下钢中的铁素体的量也增多,钢的硬度、强度也升高。
【单选题】瑞士心理学家皮亚杰创造性地提出了儿童认知发展的四阶段的理论。请指出下列不属于皮亚杰的表述()。
【单选题】We can infer from the last paragraph that ______.
A.
the proposals mentioned in the above paragraph are really radical.
B.
the education model the Netherlands and Sweden adopt are effective.
C.
the solutions of education problems involve a technique innovation.
D.
more Swedish children are educated in private schools than children in the Netherlands.
【单选题】The small mountain village where you took part in the summer camp last year lies in ______ is now part of Shanxi.
【单选题】关于凝汽器的极限真空,下列说法哪个正确()。
【多选题】下列关于亚 共析钢 的说法正确的是( )。
A.
亚共析钢是指含碳量为0.02%~0.77%之间的铁碳合金。
B.
亚共析钢的显微组织是由先共析铁素体(呈亮白色块状)与珠光体(呈暗黑色)组成。
C.
随着含碳量增加,亚共析钢的组织中铁素体量逐渐减少,而珠光体量不断增加。
D.
当含碳量大于0.60%时,亚共析钢的铁素体由块状变成网状分布在珠光体周围。
【单选题】在室温下,随着含碳量的增加,亚共析钢的()增加。
【单选题】关于凝汽器的极限真空,下列说法哪个正确?