be up to
意思是:胜任,从事于;
It could be up to two years before the process is complete.
这一过程可能要两年时间才能完成。
I'll be up to see you tomorrow.
我明天来看你。
eg:It is up to you.由你决定。轮到你了。
It is up to 5.(表示数量)最多5个。
What are you up to?你在忙什么?你居心何在?
up to now直到现在
He is not up to his work.他不能胜任他的工作