不需加偏置电压就能把光转化为电的器件，称为（）。
参考答案：光电池
It is exactly ______he often fails in the exam ______ makes his parents worried about him.
A．what; that
B．that; which
C．that; that
D．what; what
开发新型蛋白质资源的理论基础是什么？
