碳砖的特点和用途是什么？
参考答案：
特点：1、抗氧化性差2、耐高温，高温强度大
用途：主要用于矿热炉不与外界接触部位的内衬砌筑
小儿外感风寒咳嗽的主要特点是
A．咳嗽不爽，痰黄黏稠
B．咳声重浊，痰多壅盛，色白而稀
C．咳嗽频作，声重喉痒，咳痰清稀
D．咳而无力，痰白清稀
E．干咳无痰，喉痒声嘶
Only by shouting at the top of his voice__________. .
A．he was able to make himself hear
B．he was able to make himself heard
C．was he able to make himself hear
D．was he able to make himself heard
