题目

将等量的NH??????+4、PO3-4、K+、Ca2+共同置于500mL水中，再放入一些新鲜的水稻根尖，几小时后测定混合液中上述四种离子和水的含量变化如下： 项  目H2ONHK+Ca2+PO 减少量0%83%72%97%84% 答案：D His mother ____ him ____ the games.A． is allowed, to play B． doesn’t allow , to playC． doesn’t allow play D． is allowed play