Jeff Black has only one leg. When he was 12 years old, he got cancer. The doctor had to cut off most of his right leg to save his life.

    Every day Jeff walks with all artificial(人造的) leg. With the help of the leg, he can ski, ride a bike and play tennis. He can even run.

    When he was 22 years old, Jeff ran across the United States. He ran 5,150 kilometers. That was about 9.6 kilometers each day. Jeff wore out 36 pairs of running shoes and five artificial legs.

    On his way, people in every city gave Jeff some money. The money was not for Jeff himself. It was for a project, which helps people with cancer. Jeff talked to people about cancer and his disability.

    Though Jeff is disabled, he can do lots of things like a healthy man. He has finished college and now he is studying to be a lawyer. He says, "I want people to know that I ran not only for the disabled but also for everybody. I hope my spirit can cheer others up."

若分式方程$\frac{ax}{x+2}=2$的解为2，则a的值为（   ）

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    画了个金黄的太阳，送给秋天。果园里，果子熟了。金黄的落叶忙着邀请小伙伴，请他们尝尝水果的香甜。