以下哪种情况一般有可能设计单端固定桥（）
A.上颌侧切牙缺失
B.上颌尖牙缺失
C.第二、三磨牙缺失
D.第一、二磨牙缺失
E.间隔缺失
参考答案：A
If I (leave) ______ a little earlier, I would have caught the train.
How many times______ not to play with fire?
－I’m sorry. I’ll never do that again.
A．do you tell
B．had you told
C．are you told
D．have you been told
