题目

五、短文填词 Do you like friends who can teach you a lot every day? Books are s    friends because they bring knowledge to us and keep us ____(陪伴) through our life. They are so valuable that libraries are b______ to        keep them. A____ all great men are lovers of books. Franklin said that it was books that led him to success and that he could have a______(获得) nothing without books. Books are the holders of mankind’s _______(经验) and imagination. They enable us to see through the past and predict the        . So when you open a book, you would get into a已知向量向量与向量的夹角为，且。 （1 ）求向量 ；   （2）若向量与共线，向量，其中、为的内角，且、、依次成等差数列，求的取值范围．