A:甲乙丙
B:甲丙乙
C:乙丙甲
D:丙乙甲
——This history book is of great value.——Exactly. ____________ can be enjoyed from it ____________ you have a deep understanding of it, however.
化简分式 2a-4a2-4÷ 2aa2+4a+4﹣1,并选取一个你认为合适的整数a代入求值.
He had been struggling for many years and finally ________ his fantasies.
____