"知识增殖"是借鉴生物学中细胞增殖的有关概念提出来的，主要是指由一个知识引发出若干个有价值的新知识"
参考答案：对
If my father ______ here yesterday, he would have stopped me from going surfing.
A．had been
B．were
C．should be
D．has been
