My flat is near the river. I often stand in the balcony and______ the ships in the river.

A．look out of

B．look out at

C．look out from

D．look for at

生物氧化过程中合成ATP的细胞器是（）

A.内质网

B.微粒体

C.核糖体

D.线粒体

E.以上均是