一本书有５０页，小芳读了３９页，她读了全书的几分之几？'_7u+}3B/i2I.}'j6b*y;v
算式：提示-B2]-R/j7K5o8L,L(I,t9z/v6N,s'_7u+}3B/i2I.}'j6b*y;v
答：她读了全书的*Z,I;^4j.U。'_7u+}3B/i2I.}'j6b*y;v