柴油机喷油提前角过大会使示功图发生的畸变是（）
A、膨胀线呈锯齿波形
B、膨胀线高于正常值
C、示功图头部尖瘦
D、示功图头部圆滑
参考答案：C
下列哪一项不是印模的检查项目（）
A.是否清晰光滑
B.是否完整
C.有无唾液、血液、食物残渣
D.材料的强度是否正常
E.是否脱模
China _____ the WTO and became new member of it last year. [ ]
A. joins
B. joined
C. will join
D. has joined
