Is it cool? [ ]
A. Yes, it's warm.
B. It is hot today.
C. No, it isn't.
答案:C
种子萌发不包括的环境条件是( )
A.适宜的温度
B.一定的水分
C.充足的空气
D.完整的胚
冲裁模有几种导向形式?