下列能够正确表示蟾蜍发育过程的是（    ）

    Mark lived in a village far away. One day he became very ill and everyone thought he would 1 soon. They sent for a doctor. Two days 2 the doctor came and looked over the sick man.3 asked for a pen and some paper to write down the name of the medicine. But there was no pen 4 paper in the village, because no one could write.

    The doctor 5 up a piece of burnt wood from the fire and wrote the name of the medicine on the 6 of the house. “ Get this medicine for him, and he will get 7 soon. ” he said.  Mark's family and friends did not know8 to do. They could not read the strange words. Then a young man 9an idea. He took off the door of the house, put it on his carriage(马车) and drove to the nearest 10. He bought the medicine there, and Mark was soon well again.

实数a，b在数轴上的位置如图所示，则下列各式正确的是（　　）

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两个直角三角形全等的条件是（　　）