问题
填空题
受精卵的细胞分裂，称_______，分裂形成的子细胞，称_______，后者形成一个12个细胞组成的实心胚，形似桑葚，称_ _ _ __。
答案
参考答案：卵裂 裂球 桑葚胚
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受精卵的细胞分裂，称_______，分裂形成的子细胞，称_______，后者形成一个12个细胞组成的实心胚，形似桑葚，称_ _ _ __。
参考答案：卵裂 裂球 桑葚胚
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| A LESSON FROM A FROG TALE A group of frogs were jumping through the woods when two of them fell into a deep hole. All of the other frogs 1 around the hole to see what could be done to help their 2 . When they saw how deep the hole was, the rest of the group 3 that it was hopeless and told the two frogs in the hole that they should prepare themselves for their fate (命运), because they were as good as 4 . Unwilling to accept this terrible fate, the two frogs began to jump with all of their 5 . Some of the frogs shouted into the hole that it was 6 , and that the two frogs wouldn't be in that 7 if they had been more careful. The other frogs continued 8 shouting that they two should save their 9 and give up, since they were already as good as dead. The two frogs 10 jumping as hard as they could, and after several hours of hopeless 11 they were quite tired. Finally, one of the two frogs followed the calls of his fellows. Disheartened, he lay down at the 12 of the hole, and died as the others looked on in helpless sorrow. The other frog continued to jump with every bit of energy he had, 13 he was completely worn out. His companions began a new shouting to him to accept his fate, stop the pain and 14 die. The frog jumped harder and harder and, wonder of wonders, finally jumped so 15 that he sprang from the hole. 16 , the other frogs celebrated his unbelievable freedom and then gathering around him asked, "Why did you continue jumping when we told you it was impossible?" 17 their lips, the astonished frog explained to them that he was deaf, and that when he saw their gestures and shouting, he thought they were 18 him on. What he had got as 19 inspired him to try harder and finally succeeded. This simple story contains a powerful lesson. Your encouraging words can 20 someone up and help him or her make it through the day. | ||||
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