()由铸铁槽、耐火砖和捣固碳素沟料构成。
参考答案:主沟
The old farmer______ farm we spent a happy weekend was spellbound by Chinese culture.
A.on whom
B.who
C.on whose
D.whose
旋子彩画的两端靠中部位使用了带漩涡纹的花瓣,这种带漩涡纹的花瓣被称为旋子,旋子彩画因此而得名。