Come to think of it, (sentence)

Introduce something that you've just realized or just remembered this way. "Come to think of it" means something like "Here's something I just thought."

You use "come to think of it in response to something that someone asked you:

A: If you hear of anyone that's hiring, let me know.

B: OK, sure... Actually, come to think of it, I have a friend who's looking for some people.

Or you can use it to add to something that you said yourself:

I haven't been to Spain in a couple of years. You know, come to think of it, I haven't gone anywhere in the last few years.

I can't remember when the last time I (did something) was

Use this expression when you're talking about something that you haven't done in a very long time. The suggestion is that you can't remember when you did it because it was so long ago.

For example:

I can't remember when the last time I ate a McDonald's hamburger was. It has to have been 10 years ago at least.

host (a party or event)

"Hosting" a party means that you do the planning or provide the space for it. These are all examples of hosting:

• you invite people to your house for a party
• your friend organizes a party and you let her use your house for it
• you invite people to your office for a networking event
• you rent a gallery and organize an art show there

The person who is hosting the party is the "host".