下列关于主根和侧根的叙述，正确的是[ ] A．主根向下伸长与_爱下问搜题

搜题请搜索小程序“爱下问搜题”

问题选择题

下列关于主根和侧根的叙述，正确的是[ ]

A．主根向下伸长与茎相连，侧根是从主根周围生出的

B．由种子中的胚根发育成的根叫侧根，与茎相连的根叫主根

C．任何植物都是主根发达，侧根不发达

D．垂直向下生长的根是主根，横向生长的根是侧根

答案

答案：A

阅读理解

阅读下列短文，判断正(√)误(×)。

Spear and Shield

      A man is selling his spear and shield at the market. He is shouting loudly, " Come and look. The best spear and
the best shield in the world."
      Some people get together. He is very happy. He puts up his spear and says, " Look at my spear. It's very
sharp. It can pierce through any shield. " And then he puts up his shield, " Look at my shield. It's very hard. It
can stop any spear."
      And then someone asks him, " Then what will happen, if you pierce your shield with your spear? "
      The man is very embarassed and says nothing.
( ) 1. The man is selling his spear and shield.
( ) 2. Some people get together and the man is sad.
( ) 3. Someone asks him, " How do you feel? "
( ) 4. The man is very angry at last.

填空题

电能表是用来测量电路消耗的仪表．小红家的电能表9月底的示数为

，10月份小红家共用电50kW?h，10月底小红家的电能表的示数为 kW?h．50kW?h合 J．