问题 填空题

在△ABC中,a,b,c分别为角A,B,C所对的边.已知角A为锐角,且b=3asinB,则tanA=______.

答案

在△ABC中,角A为锐角,且b=3asinB,由正弦定理可得 sinB=3sinAsinB,∵sinA≠0,

故sinA=

1
3
,∴cosA=
1-sin2A
=
2
2
3
 tanA=
sinA
cosA
=
2
4

故答案为

2
4

完形填空
完形填空
     Valentine's Day was the time my father chose to show his love for the special people in his life.Over the
years I fondly (天真地) thought__1__him as my "Valentine man".
     My first recollection of the__2__he could bring to Valentine's Day came when I was six.That morning
at the breakfast table I found a card and a giftwrapped package at my chair.The card was__3__"Love,
Dad" and the gift was a ring with a small piece of red glass to__4__my birthstone,a ruby (红宝石)。There
is__5__difference between red glass and rubies to a child of six,and I remember__6__that ring with pride
 that all the cards in the world__7__not surpass (超越).
    __8__I grew older,the gifts gave__9__to heartshaped boxes filled with my__10__chocolate and always
included a__11__card signed "Love,Dad".In those years my thankyou became__12__of a perfunctory
(敷衍) response.The cards seemed less__13__,and I took for granted that the Valentine would__14__be
there.I had__15__my hopes and dreams in receiving cards and gifts from "significant others" and "Love,
Dad" just didn't seem quite__16__.
     His final card remains on my desk today.It's a__17__of how special fathers can be and how important
it has been to me over the years to know that I had a father who continued a__18__of love with simple
acts of understanding and an ability to express happiness over the people in his life.
     Those things never__19__,nor does the memory of a man who never__20__being my valentine.
( )1. A.of      
( )2.A.memory  
( )3.A.read      
( )4.A.recover    
( )5.A.much    
( )6.A.having    
( )7.A.could    
( )8. A.Because  
( )9.A.room      
( )10.A.favorite  
( )11.A.usual    
( )12.A.less      
( )13.A.important
( )14.A.surely    
( )15.A.let      
( )16.A.suitable  
( )17.A.signal    
( )18.A.tradition
( )19.A.lose      
( )20.A.thought  
B.about      
B.magic      
B.written    
B.resemble   
B.little    
B.owning    
B.did        
B.Since      
B.way        
B.lovely    
B.common    
B.little    
B.beautiful  
B.always    
B.kept      
B.enough    
B.certificate
B.hobby      
B.die        
B.wanted    
C.up        
C.puzzle    
C.shown      
C.represent  
C.great      
C.we aring  
C.must      
C.When      
C.honour    
C.dear      
C.strange    
C.more      
C.familiar  
C.regularly  
C.placed    
C.effective  
C.consequence
C.habit      
C.miss      
C.tried      
D.over      
D.present    
D.signed    
D.replace    
D.less      
D.watching  
D.should     
D.As        
D.seat      
D.precious  
D.special    
D.much      
D.standard  
D.often      
D.remembered 
D.sacred    
D.reminder  
D.custom    
D.appear    
D.stopped    
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