A:2a+1
B:2a-1
C:-2a-1
D:a2
What do you see?
A number of new functions ________ to the computer since it was first invented in 1946.
①激发和调动中小企业的活力和创造力
②促进各种所有制经济平等参与市场竞争
③发挥中小企业在经济发展中的主导作用
④保障各种所有制经济在国民经济中的平等地位
My sister asked me ____ ____ ____ ____ some candies for her on my way home.