会导致前庭沟处小溃疡的是
A．基托边缘过长或过锐 B．基托变形 C．基托与黏膜不密合 D．人工后牙覆盖过小 E．垂直距离过低
参考答案：A
.Great changes______in the city and a lot of factories______.
A．have been taken place…have been set up
B．have taken place…have been set up
C．have taken place…have set up
D．were taken place…were set up
型钢弯曲可采用什么方法？
et up