如图所示的是电解水实验装置．通电一段时间后，在两个试管中分别收集到气体a和气体b．请回答：
（1）电解水时，将______转化为化学能；
（2）气体a为______；
（3）实验室检验气体b的方法是______．
（1）电解水时，将电能转化为化学能；故填：电能．
（2）气体a为氢气．故填：氢气．
（3）实验室检验气体b的方法是把带火星的木条伸入b中，如果带火星的木条复燃，说明b是氧气．故填：把带火星的木条伸入b中，如果带火星的木条复燃，说明b是氧气．
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| John loved playing basketball after school. John's parents were anxious about their son because he 1 half of his spare time playing basketball, even though he would soon 2 the college entrance exam (高考). Many evenings, John returned home 3 at the beginning of the new term. His parents told him to concentrate more 4 his studies, but their words went in one 5 and out the other. His parents were so angry that they 6 his basketball. From that day on, John returned home on time but locked 7 in his room. At first, his parents dreamt their son could study hard to enter a top university. But 8 news shattered (破灭) their dream. John's pre-exam test scores were 9 . One night, John's mother looked into his room and 10 him reading a basketball magazine. So John's parents discussed the matter. They 11 to make a deal (约定) with John. If John scored high marks in the following tests, he could get his ball back and 13 once again; if he failed, they would keep the ball 12 he improved. John 14 reading his magazines. He started working hard. He started getting high marks and got his 15 back. The ball stayed with John until he entered a top university. | ||||
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