【单选题】It was in the small house _____ was built with stones by his father _____ he spent his childhood.
【单选题】When I saw his pale face, I ________ what ________. [ ]
A.
realized, had happened
B.
was realizing, was happening
C.
realized, has happened
D.
has realized, had happened
【简答题】在换热器中参加换热的两种流体在间壁两边分别以相反的方向流动,称为( ),若以相同的方向流动,则称为( ),在工业生产中,一般都采用( ),只有在特殊情况时,才采用( )。
【简答题】What had his small workshop become?
【多选题】我国的安全生产工作格局是()、全社会广泛支持。
【多选题】关于线性方程组解的结构,下列说法正确的是( ) .
A.
齐次线性方程组的通解就是它的基础解系的任意线性组合.
B.
非齐次线性方程组的通解就是它的基础解系的任意线性组合.
C.
非齐次线性方程组的通解就是对应齐次线性方程组的通解加上该非齐次线性方程组的一个特解.
D.
非齐次线性方程组的通解就是它的基础解系的线性组合加上对应齐次线性方程组的一个特解.