树脂的密度主要取决于树脂的交联度及其种类。对于含同一类交换基团的树脂,交联度高的,其密度就大;对于交联度相同的树脂,阳树脂的密度一般比阴树脂的大。()
参考答案:对
Among all these flowers _____ a kind of red rose, which was given by my friend. [ ]
A. is included
B. include
C. were included
D. included
下列选项中,属于一级负荷的是( )。
A.一类高层建筑的消防控制室、消防水泵和消防电梯B.中断供电将造成公共场所秩序混乱C.中断供电将造成公共场所秩序严重混乱D.中断供电造成较大经济损失