节点分析法的互电导符号恒取负(-)。
参考答案:对
改错。
( ) 1. Are you hungry? Yes, I have. ________________
A B C
( ) 2. We doesn't go to school on Sundays. ________________
( ) 3. They are make a cake now. ________________
镁碳砖中MgO含量高时,可以提高砖的(),()和()。