I can't right now, but maybe later.

我现在办不了，可能过几天吧。

Unfortunately, I've had a few things come up.

不好意思，我手头有一些事情要处理。

I'm trying to focus on finishing off some other things.

我正忙着处理一些其他的事情呢。

Sorry but that isn't my strong suit.

不好意思，那个不是我的强项。

I'm sure you will do fine on your own.

我相信你自己可以做好的。

I'm afraid I'm committed to something else.

我有别的事情要做。

I can't at that time, but I'm happy to help you with something else later.

这会儿我帮不上忙，不过以后有事我很愿意帮你。

I really don't enjoy that kind of activity.

我不喜欢那样的活动。

I'm sorry, but I have an emergency to attend to.

不好意思，我有个急事要处理。