He more than 5,000 English words when he entered the university at the age of 15.
A. has learned
B. would have learned
C. learned
D. had learned
网友回答
A. has learned
B. would have learned
C. learned
(答案→)D. had learned
解析：此题容易误选C,学生见到过去时间点，就会依据平时的经验选择一般过去时。其实此题应选D。掌握了5000多个单词并非在15岁上大学时发生，而是早在之前就完成了，过去的过去，所以要用过去完成时。此句话的汉语意思是：在他15岁上大学时，就已经掌握了5000多个单词了。