— Where does your mother work?
— ____________
A:She likes singing.
B:She works in a post office.
C:She is a scientist.
“断食清肠”的减肥方法主要就是绝食,科学证明这种做法对身体危害较大.在绝食期间,体内分泌量比正常进食明显增加的激素是( )
如图,一张矩形纸片ABCD的长AB=a,宽BC=b.将纸片对折,折痕为EF,所得矩形AFED与矩形ABCD相似,则a:b=( )
下列单位换算过程正确的是( )
化简(-2a)2-2a2(a≠0)的结果是( )