last minute helper 事后帮手

Last minute helper is that person who shows up AFTER everything else is done and offers to do something AFTER everything is already finished.

Last minute helper指所有事情都完成以后才出现，或者别人把所有事情都做完后才提出帮忙的人，我们称为“事后帮手”。

For example:

Joe showed up when we got all the dishes ready. He offered to set the table, but Mary already did it. He is definitely a last minute helper, you cannot count on him.

乔来的时候，我们已经做好菜了。他要求摆置餐桌，可是玛丽早就摆好了。他绝对是个事后帮手，一点都指靠不上。