问题 选择题

已知△ABC三边之比为3:4:5,与其相似的△DEF的周长为24,则S△DEF为(  )

A.24

B.48

C.12

D.32

答案

∵△ABC与△DEF相似,

而△ABC三边之比为3:4:5,

∴△DEF的三边之比为3:4:5,

设三边分别为3k、4k、5k,

∴3k+4k+5k=24,解得k=2,

∴△DEF的三边分别为6、8、10,

∴△DEF为直角三角形,

∴S△DEF=

1
2
×6×8=24.

故选A.

单项选择题

I first went to hear a live rock concert when I was eight years old. My brother and his friends were all fans of a heavy metal group called Black Wednesday. When they discovered that Black Wednesday were going to perform at our local theatre, they all bought (21) for the performance. However, at the last minute, once of the friends couldn’t go, so my brother offered me the ticket. I was really excited!

I remember the buzz (嘈杂声) of excitement inside the theatre as we all found our seats. After a few minutes, the lights went down and everybody became quiet. I could barely make out the stage in the (22) . We waited. Then there was a roar from the crowd, like an explosion, as the first members of the band stepped onto the stage. My brother leaned over and shouted something in my ear, but I couldn’t hear what he was saying. The first song was already starting and the music was as (23) as a jet engine. I could (24) the drum beats and bass notes in my stomach.

I can’t recall any of the songs that the band played. I just (25) that I really enjoyed the show and didn’t want it to (26) . But in the end, after three encores (加演), the show finished. We left the (27) and walked unsteadily out onto the pavement. I felt a little dizzy, as if I had just woken from a long sleep. My ears were still (28) with the beat of the last song.

After the (29) , I became a Black Wednesday fan too for a few years before getting into other kinds of music. Once in a while, though, I listen to one of their songs and (30) I’m back at that first show.

28()

A.aching 

B.burning 

C.ringing 

D.rolling

单项选择题