目前我国农业灌溉用水的有效利用率仅为40%。在全国境内的700多条重要河流中,有50%的河段、90%以上的沿河水域污染严重。这反映了我国( )①水资源人均占有量少②对水资源的利用不够科学,浪费严重③水资源污染状况严重④水资源的总量不够
A:①②③
B:②③
C:②④
D:③④
— I missed the beginning of ________ cartoon The Lion King.— What a pity! You should leave school half _______ hour earlier.
下列各组词语中划线的字,读音全都正确的一组是( )
The story was written in______ easy English_____ even the seven-year-old child could understand it.
将边长为2的正△ABC沿BC边上的高AD折成直二面角B﹣AD﹣C,则三棱锥B﹣ACD的外接球的表面积为____