森林里空气格外清新，有“天然氧吧”之称，是因为植物光合作用产生了 [ ]
A．H2
B．O2
C．N2
D．CO2
答案：B
I have bought two ballpens, ____ writes well. [ ]
A. none of them
B. neither of them
C. neither of which
D. none of which
本段运用机车用油凭“司机报单”领取，发放人员填写“燃油请领单”两份，（）送财务、统计各一份。
