如图分别表示青蛙发育过程中的四个阶段．能正确反映青蛙发育全过_爱下问搜题

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问题选择题

如图分别表示青蛙发育过程中的四个阶段．能正确反映青蛙发育全过程的是（　　）

A．①②③④

B．②③④①

C．②③①④

D．④②①③

答案

蛙的生殖发育过程为：雄蛙先鸣叫吸引雌蛙，雌蛙来后雌雄蛙抱对，促进两性生殖细胞排出，两性生殖细胞在水中结合形成受精卵，许多受精卵在一起形成卵块，受精卵孵化出小蝌蚪，小蝌蚪先长后肢，再长前肢，最后尾巴逐渐消失，变成小幼蛙，幼蛙逐渐长成成蛙．即②受精卵→③蝌蚪→①幼蛙→④成蛙．

故选：C．

单项选择题

下列哪项不是促进内皮细胞合成或释放PAF的物质（）

A.PGI₂

B.凝血酶

C.TNF

D.IL-1

E.胶原

完形填空

Many of us spend a great deal of time and energy trying to prove that we are right and others are wrong. Many people believe that it’s their job to 36 others how their positions, statements and points of view are   37  and that in doing so, the person they are correcting is going to somehow   38  it, or at least learn something. Wrong！
Think about it. Have you ever been   39  by someone and said to him, “Thank you so much for showing me that I’m wrong and you’re right.” Or has anyone you know ever   40  you when you corrected him, or made yourself “right” at his 41  ? Of course not. The truth is, all of us   42 to be corrected. We all want our position to be   43  and understood by others. Being listened to and heard is one of the greatest   44  of the human heart. And those who learn to   45  are the most loved and respected. Those who are in the   46  of correcting others are often hated and   47 .
A wonderful way of becoming more peaceful and loving is to practice 48    others the joy of being right--- give them the glory.   49 correcting. When someone says, “I really feel it’s important to…” rather than   50  and saying, “No, it’s more important to…” , simply let it go and allow his statement to   51 . The people in your life will become less defensive and more   52 . They will appreciate you more than you could ever have   53  possible. You’ll discover the joy of joining in and seeing other people’s 54  , which is far more rewarding than a battle of egos（自我意识）. Starting today, and let others be “ 55  ” most of the time.

A．unbelievable

D．unimportant

C．shortcomings

A．working out

D．putting off