题目内容：

阅读下面材料，在空白处填入适当的内容(1个单词)或括号内单词的正确形式。

Recently a photo which shows a dentist knelt to carry out an operation for a 9-year-old girl spread online.

The operation 41.___________ (carry) out on Sept 5 by Qu Tiejun, a dentist in the dental hospital of the Fourth Military Medical University. He was somewhat surprised that he drew so 42.___________ attention after the photo spread online.

"It was my duty 43__________ (cure) the patient. It didn't matter if I was kneeling or standing during the procedure," said Qu. According to the dentist, the 9-year-old girl came from a village in Baoji in Shaanxi. She suffered an oral injury, 44.__________ required surgery.

"I had to do the operation by 45.__________ (kneel) because the mouth was only 5 mm and could not be seen with a common surgical microscope," said Qu.

The doctor put 46.___________ operation mirror on his head and had to kneel down in order to get a proper angle for him to see the 47.__________ (injure) part of the girl's mouth.

It took Qu 40 minutes to complete the operation. 48.__________ asked why he did not raise up the 49.__________ (surgery) bed to do the operation, Qu explained that it still did not give suitable angle for the operation once the bed was raised.

A nurse took the photo of Qu’s kneeling operation and put 50___________on her WeChat.