问题 单项选择题

双绞线电缆中的4对线用不同的颜色来标识,EIA/TIA568A规定的线序为 (9) ,而EIA/TIA568B规定的线序为 (10)

A.橙白 橙 绿白 蓝 蓝白 绿 褐白 褐

B.蓝白 蓝 绿白 绿 橙白 橙 褐白 褐

C.绿白 绿 橙白 蓝 蓝白 橙 褐白 褐

D.绿白 绿 橙白 橙 蓝白 蓝 褐白 褐

答案

参考答案:C

解析:

[分析]: 双绞线电缆中的4对线分为不同的颜色,T568A、T568B规定的线序分别如下图(a)、(b)所示。 对于直通线,双绞线的两个接头都按568B线序标准连接。对于交叉线,双绞线的一头按568A线序连接,另一接头按568B线序连接。

单项选择题
单项选择题

"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.

6().

A.spirits

B.feelings

C.courage

D.strength