瓷全冠的优势有
A．不导热、电
B．生物相容性好
C．色泽稳定
D．强度高、脆性小
E．模拟自然牙逼真
参考答案：A,B,C,E
A: Danny, are these your shoes?
B: _____. [ ]
A. My shoes are brown.
B. Yes, I am.
C. Yes, they are.
D. These are my shoes.
试述噬菌体及其实际意义。
