试戴支架合适后，待完成义齿后发现支架变形，不能就位，其原因最可能是 （）

A.模型变形

B.填塞塑料过早

C.基托厚薄不均

D.热处理升温过快

E.开盒时石膏剪的用力方向不对

In today's class, the students were asked to () their mistakes on the exam paper and put in their possible corrections.

A．cancel

B．omit

C．extinguish

D．erase