— What can you do?
—
A:I can write.
B:I like swimming.
C:I go shopping.
____ the cat feels!
如图,∠AOB是⊙O的圆心角,∠AOB=90°,则弧AB所对圆周角∠ACB的度数是( )
下列关于cDNA文库和基因组文库的说法中,不正确的是( )