I know that (clause), but...

This is a good phrase to use when you're trying to persuade someone. You show that you understand their possible disagreements before you express your own point. For example:

Listen - I know it's none of my business, but you should probably apologize to her.

I know you're busy, but can you help me out with this?

You can use the word "that", or leave it out in more casual spoken English.

(something) is a risk

You say that something is "a risk" when there's a high chance that you will hurt yourself, lose money, or lose.

pull it off

Use "pull it off" when you're talking about trying something difficult or risky, and succeeding. For example, you can "pull off":

• a dangerous skateboarding trick
• getting a really beautiful woman's phone number
• passing a test that you only started studying for the night before

If you tried something difficult but you didn't succeed, you say:

I wasn't able to pull it off.

a bit of a (something)

The phrase "a bit (adjective)" is similar in meaning to "a little":

It's a bit cold out.

It's a bit intimidating.

The meaning of "a bit of a ___" is the same, but you use it before a noun instead of an adjective:

I know that it's a bit of a risk, but I really think we can pull it off.

There seems to be a bit of a lag.