（）of them is going to sing a beautiful song for the sick kids

第一题选 Each 因为只有它作主语谓语才用单数is.前两个词作主语谓语用复数are.最后一个everyone只有写成every one才可接介词of ..所以也是错的.
第二题,当不出现谓语时像这道题只有all of us时用哪个词取决于句意思.如有谓语看谓语形式来选.也就是语法中的主谓一致.如
Each of us is happy.
All of us are happy.
Both of us are happy.后面只有cheeredupWhen Mr Wang told us this good news,all of uscheeredup这道题和上面不同因为它不涉及主谓一致. cheered是过去式.(无数的变化)主语是单数或复数都一样.但前面的考查根据谓语的数来判断主语用哪个代词.