--- I am sorry I stepped outside for a smoke. I am very tired. --- There is no ______ for this while you are on duty. A. reason B. excuse C. cause D. explanation 答案:B在做托里拆利实验时,测得管内、外水银面高度差是760毫米,然后再向水银槽里注入水银,使 槽里水银面上升10毫米,则这时管内外水银面高度差为:( )A. 770毫米; B. 765毫米; C. 760毫米; D. 750毫米。