Using subjunctive mood:I think it very important for the textbooks to be available before school starts.

【正确答案】正确答案：I think it very important that the textbooks(should)be available before school starts．

【答案解析】解析：本题要求转换为虚拟式，只要把important后面的不定式转换为从属分句，从属分句中的谓语动词用(should)+动词原形即可。