某市努力改善空气质量,近年来空气质量明显好转,根据广州市环境保护局公布的2006-2010这五年各年的全年空气质量优良的天数,绘制折线图如图.根据图中信息回答:
某蛋白质由m条肽链、n个氨基酸组成。该蛋白质至少含有氧原子的个数是( )
若关于x的分式方程 x−6x−5 +1= k5−x 有增根,则k的值是____.
如图,在菱形ABCD中,M,N分别是边AB,BC的中点,MP⊥AB交边CD于点P,连接NM,NP.
—Can you lend me the book Passing by Your World?
—Sorry. I returned it to the library just now. Maybe it is still ________.