若双曲线x2-y2b2=1(b>0)的离心率为2,则实数b等于( )
Jim often ____ ____ ____ a prince when he is at a party.
你想知道他听到了什么,可以问:What do you see?
yóu lǎn
gōng yì pǐn
zhuàng guān
chū shòu
____
tān diǎn
chén liè
gòu sī
guān shǎng