用显微镜观察经健那绿染过色的人口腔上皮细胞,可以观察到线粒体的原因是( )
Elephants can be ______ years old.
He helped his mother ________ the housework. A. do B. does C.did
Isawaboy_____awaywhenIpassedthepark. A.runB.ranC.for
Itistime_____home. A.goB.togoC.togoto
I get up _____a quarter to six______a hot morning.