at his knowledge all the students showed their respect for their teacher.A. AmazedB. Be

问题补充：

at his knowledge, all the students showed their respect for their teacher.

A. Amazed

B. Being amazed

C. Amazing

D. Having amazed

答案：

(答案→)A. Amazed

B. Being amazed

C. Amazing

D. Having amazed

解析：考查形容词用法。固定词组be amazed at…对…感到惊讶；本题amazed at…是对主语all the students进行修饰的。句意：对于他的知识感到很惊讶，所有的学生都很尊敬他们的老师。故A正确。