邓 * * 理论指出社会主义的本质是（），（），消灭剥削，消除两极分化，最终达到共同富裕。
参考答案：解放生产力；发展生产力
She ___ volleyball regularly for many years when she was young．
A．was playing
B．played
C．has played
D．had played
丝网印刷术是什么时候发明的？
