“Actually, now's not a good time.”
At work, you're working hard to prepare for a presentation that you're giving in less than an hour. A co-worker comes by to chat about a problem that she's having with another co-worker. You don't have time to talk to her about this, so you say this.
Actually, now's not a good time.
Use this to tell people something that's unexpected or different from what they are expecting to hear:
"Actually," is really useful for correcting people. For example, if you're putting a puzzle together with someone and they put a piece in the wrong place, say:
Actually, the blue piece goes over here.
This phrase means that you can't do something right now because you're too busy, too upset, you're not prepared, or some other similar reason.
"Now" is not usually used as the subject of a sentence. For example, it's incorrect to say "Now is 5 o'clock". Instead, you say:
It's 5 o'clock now.
But "Now is good" or "Now is not good" are the exceptions to this rule:
A: Hey, when do you think we can sit down and go over the budget?
B: Now's good.
A: Do you mind if I ask you a few questions about it?
B: Sorry, now's not good actually. Can I call you back later this afternoon?