形成LE细胞必须具备的决定性条件是()。
A.免疫功能健全
B.补体活化
C.患者血清存在LE因子
D.具备有吞噬能力的细胞
E.受累或退变的细胞核
参考答案:C
No conclusion ______about whether to tear down the old buildings for a theme park until several
discussions have been made.[ ]
A. will be reached
B. is reached
C. is being reached
D. had been reached
单闭环比值控制系统的优点在于()。
A.两种物料流量的比值较为精确
B.提降负荷比较方便
C.主流量一旦失调,仍能保值原定的比值
D.两种物料流量的比值实施方便