蘑菇、香菇和银耳中含有（）物质，具有提高人体免疫功能和抗肿瘤作用。
A.脂类
B.花生四烯酸
C.多糖
D.亚油酸
参考答案：C
---- ____________ he has known the good news.
---- ______ is no wonder he is so excited.
A．It is likely that; It
B．It is probably that; There
C．He is likely that; There
D．He is possible that ; It
压缩机油泵出口管线上，有（）。
A.油冷器
B.油滤器
C.油稳压器
D.油压调节阀
