我国监狱坚持监狱人民警察对服刑罪犯的直接管理，在人民警察与罪犯之间不能存在一个阻断层。
参考答案：对
According to a new survey carried out by an American university, learning______ second language can result in_______ increase in the power to learn your native tongue.
A．a; the
B．不填; the
C．a; an
D．the; an
物理电流强度
