题目

 Leave the reference books behind, __________ you won’t be able to think independently. A) or                            B) and                          C) so                           D) but 答案：A9．下面各组中互为倒数的是（　　）A．0.7和$\frac{1}{7}$B．0.25和$\frac{1}{4}$C．1$\frac{2}{7}$和$\frac{7}{9}$