串级调节系统是由主控制器和副控制器()组成。
A.连接
B.相并连接
C.相串连接
D.独立
参考答案:C
在下列疾病中,动物下体水肿明显的病是( )。
A.痛风
B.肺炎
C.锰缺乏
D.栎树叶中毒
E.碘缺乏
One of the requirements for a fire is that the material ____ to its burning temperature.[ ]
A. is heated
B. will be heated
C. be heated
D. would be heated