读太阳光照图(如图),完成下题.
如图,小明用动滑轮在10s内将重400N的物体匀速提高了5m ,若这一过程中动滑轮的机械效率是80%,则下列结论中正确的是( )
用方框那所给的单词或短语完成下列各句,注意形式变化
(1) Where was your mother? --She ____ .(2) Let's____ school by bus.(3)The twins like ____ .(4)____ is fun for the twins.(5) I ____ I'm late.(6) Don't ____ school next time.(7)What ____ with you? I'm____ ill.(8)____ do you go to the park? Once a week.(9)Where ____ you ____ ? Canada.(10) Look! Liu Mei____ .