at the moment,at that moment,in a moment,a moment ago的区别与具体翻译、句型

at the moment 的意思是“现在”“此刻”，常与一般现在时或现在完成时连用。例如：
I have got enough to do at the moment.
但是，at the moment 有时也作“当时”讲，用于过去时态。例如：
I didn't buy that book, because I had no money on me at the moment.

at this (that) moment 的意思是“此时”、“当时”、“那时”，可与现在时、过去时连用。例如：
Parents may feel sad at this moment.

for a moment 是指“片刻”、“一会儿”，表示持续的时间。例如：
For a moment she just stood there, unable to believe what had just happened.

in a moment 的意思是“很快”、“立即”、“马上”。例如：
I'll be ready in a moment.

a moment ago,刚才，表示刚才发生的事情。
I saw Jim a a moment ago。

at the moment这时
at that moment那时
都用于叙述事情时用，一般at that moment是叙述过去的事情
in a moment过一会儿
a moment ago刚刚
i'll be there in a moment
he leaved here a moment ago