题目

When and where to go for the on-salary holiday ______ yet. A. are not decided        B. have not been decided C. is not being decided    D. has not been decided   答案：D不定式作主语，谓语动词用单数。海洋中电鳗有放电现象，其电能是（   ）A．由热能转变而来B．有机物氧化分解释放的化学能转变而来C．由光能转变而来D．由ATP转变成ADP时释放的化学能转变而来