危害最大的是（）
A.牙髓炎
B.根尖周炎
C.死髓牙
D.牙周炎
E.残根
参考答案：D
电焊工人在焊接时戴上防护眼罩是为了防止 的伤害，卫星上常用 探测器拍摄照片。
His increasing financial difficulties made him so ____ for a job that he would have done anything.[ ]
A. optimistic
B. hopeful
C. active
D. desperate
