已知等差数列{a_n}的公差是2，且a₁+a₂+a₃+…+a₁₀₀=100，那么a₄+a₈+a₁₂+…+a₁₀₀=（　　）

A．25

B．50

C．75

D．100

Only in this way____to make improvement(提    高)in the operating system.   [      ]

A. you can hope    

B. you did hope    

C. can you hope    

D. did you hope