志愿者主要有哪些义务？

A. 正确
B. 错误

A. reduce air charge turbulence
B. induce air swirl
C. deflect hot combustion gas away from the valves
D. oppose the effects of piston induced squish

A. 耗费资金数额大
B. 投资次数少
C. 投资风险大
D. 投资收益大