"It’s no use, Mum," said Johnny. "I’m just no good at dancing."
"You’ve got to keep trying. Tonight will be (1) , dear. Try a turn with that pretty Lisette. "
Johnny (2) . Every Saturday night used to be the best of the week. He and his parents went to the (3) at the Club, where his hero, Alcide, played the accordion with the band. But lately everything had changed. Now that Johnny was older, he was (4) to dance with a girl!
(5) Johnny and his parents arrived at the Club, music had already started. Johnny got up his (6) to approach Lisette. "May I have this dance" Johnny asked. "That’s all right."said Lisette. Johnny struggled to keep up with Lisette’s (7) steps, but he was always one beat behind her. Then Johnny heard his friend Pierre say, "Look! Johnny has two left feet!" (8) burst from the crowd. Johnny (9) and ran outside, determined never to go to another dance.
The next Saturday, Alcide (10) to Johnny’s house for some potatoes. He happened to hear Johnny playing the accordion. Alcide’s eyes (11) . "Bring that accordion and play some songs tonight," Alcide said. Then he drove off, leaving Johnny staring open mouthed (12) him.
At the Club, Johnny scanned the crowd for Lisette and (13) her. The band played for a long time before Alcide said, "Dear friends, I got a (14) for you tonight. Young Johnny is going to join us!" (15) , Johnny stepped up on the platform, his eyes on the floor. He began to play, and the band (16) behind him. When the song ended, he heard cheers. Johnny kept playing until the dance was (17) . "You did a fine job tonight. Play with us again next Saturday night, " Alcide said. "Yes, sir! " said Johnny. (18) he went outside, Johnny saw Lisette and her friends near the door. Lisette stepped (19) , smiling. "You played really good tonight!" she said."Thank you," Johnny blushed. As he walked on, Pierre (20) moved out of the way for him to pass.Johnny patted his accordion. Come to think of it, in his whole life, he had never once seen Alcide out on the dance floor.
5().
A．If
B．Since
C．Though
D．When
题目分析：（1）高锰酸钾能氧化盐酸和氢硫酸，硝酸本身具有强氧化性，故选硫酸；（2） 由进行操作Ⅰ后得滤液，故操作Ⅰ应为过滤，由于MnO2难溶于水操作Ⅱ后得KMnO4溶液，故操作Ⅱ为过滤，进行操作Ⅲ后使溶液变成了晶体，故操作Ⅲ为蒸发；（3）由产物及元素的化合价可知氧化剂应为KClO3，滤液中主要成分是K2MnO4，酸化后得到KMnO4和MnO2，故方程式为：3MnO42－＋4H＋=2MnO4－＋MnO2↓＋2H2O；（4）由题意及电子守恒可得关系式为：