如图,P是∠α的边OA上一点,且点P的坐标为(3,4),则sinα的值是( )
A:34
B:35
C:45
D:无法确定
下列有关催化剂的说法中正确的是( )
Many buildings in this city need repairing, but the one __________ first is the library. ( )
用如图①中的长方形和正方形纸板作侧面和底面,做成如图②的竖式和横式的两种无盖纸盒.现在仓库里有m张正方形纸板和n张长方形纸板,如果做两种纸盒若干个,恰好使库存的纸板用完,则m+n的值可能是( )
对逆反心理认识正确的是( )
There was something wrong with the line. We couldn't _______ each other clearly.