Many Chinese students think science subjects are foreign languages.A. more difficult asB.

问题补充：

Many Chinese students think science subjects are foreign languages.

A. more difficult as

B. less difficult than

C. much difficult than

D. so difficult as

答案：

A. more difficult as

(答案→)B. less difficult than

C. much difficult than

D. so difficult as

解析：比较级的结构为比较级+than，difficult的比较级为more difficult或less difficult，平级的结构为as+形容词原级+as，否定句中第一个as可用so，故本题选B。