According to the meaning, there are 16 math books and English books. There are 17 Chinese books and English books.

Because Chinese is more than math1;

So there are 35 books about math, Chinese, English and history.

Chinese and history * * * is: 35- 16= 19 (Ben);

Mathematics and history * * * is: 35- 17= 18 (Ben).

So let's assume that nine books are all math, so we have to:

English: 16-9=7 (Ben); The language should be: 9+ 1= 10;

Then the history is: 35-9-7- 10 = 9.

Because the number of books is different.

So there are nine math books that don't match the meaning of the question. Therefore, the assumption is not valid.

Similarly, it is impossible to have nine language books.

When there are 9 English books, there are 7 math books, 8 Chinese books, 1 1 history books, which are consistent with the title.

So nine of these books are English books.

So fill in: English.