A：黑格尔辩证法的合理内核和费尔巴哈唯物主义的基本内核
B：李嘉图为代表的古典经济学
C：黑格尔的唯物主义和费尔巴哈的辩证法
D：圣西门、傅立叶、欧文的空想社会主义
– Why don't you go out to have fun?
– You see, we are studying for the tests these days. And we are ______ busy_____ we can't go out.
