—What do you think of your English teacher?
—He is a strict teacher,but all his students show respect for.
A.that B.the one C.who D.one
解析：考查代词.根据题意可知,空格部分指代a teacher,泛指这样一个既对学生严格又深受学生尊敬的老师.所以选D项.
答案：D
知识拓展:one指代上文提到的可数名词的单数,是泛指；the one指代上文提到的可数名词的单数,是特指；that指代上文提到的可数名词的单数或不可数名词；it指代上文提到的可数名词本身.
这是我从http://lyh2881.blog.163.com/blog/static/60176559201141445525108/查到的