at once right now right away at the moment 区别、比如用在哪个时态

at once right now at once ,right now,right away和now的区别 right now 和 at once 的区别? at once 和 right now 可以互相转换吗？ right away=at once=right now?right away和at once都是立刻的意思,而right now不是现在的意思吗? at once right now right away at the moment 区别、比如用在哪个时态 at the moment , at once,right now,right away区别用法和意思。 he is doing homework___.A.right away B.right now C.at once D.immediately in no time,right away, right now, at once 有何差别,细讲 请问right now和right away都是at once的同义词吗? on the spots/at once/ right now/right away的区别 at once 和right now ,now 词性是不是一样的?如题 right now 的近义词 A just now B in a while C at once at once的同义词是at the momeng或right now是吗? at once &right away区别, either,also和too怎么区分?还有right now,at once怎么区分? at once、right now等词可以用在过去式的句子中表示马上吗? Good morning,ladies and gentlemen.1．I will leave at once / right now / right away.2．I am leaving at once/ right now / right away.哪句更符合英美人表达习惯?