⤵︎Now,

At the beginning of a statement or question, pronounced with a falling intonation and followed by a pause, Now is used to indicate that the speaker is about to make an important point based on something they just explained. This important point can be a warning, an exception, an explanation, a question... anything that the speaker wants you to pay particular attention to. In other words, this is a short way of saying «Having said that,...». It's usually followed by a pause and can even be accompanied by a gesture like holding up one finger to make it clear that you're about to say something important.

In this snippet, Nina tells Cliff about the surprise party, he protests, and she defends herself with several points: the party wasn't her idea, it was his parents' idea, and couldn't say no to them. But then she wants to get to what's really important: whether or not he wants to go ahead with the party, and she calls attention to this question by using Now,... In this context, it means «There! I made my points. But this is what I need to know: ...»

Cliff hates surprises and Nina knows it. Unfortunately, his parents are planning a surprise birthday party for him.

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Nina: Cliff, not to be a party pooper, but you should know that you're parents are planning to throw you a surprise barbecue for your birthday.

Cliff: What?! You have got to be joking! You know how I feel about surprise parties.

Nina: Yes, Cliff, I know perfectly well. But it wasn't my idea. The party was your parents' idea, so I wasn't really in a position to say no. Now, do you want to go ahead with the party or do you just want to spend the day with the kids and me? I'm fine with either option. I'll just tell them it's off and they'll have to deal with it. 

Cliff: No... there'll be no end to the drama and you'll come off like the bad guy. I guess we have no choice. 

Nina: Fine, but then please act surprised and make the best of it. The last thing I need is for your family to think I tipped you off.

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⦿ not to be | short for I don't mean to be...⦿ party pooper | someone who ruins a party or surprise, or even other people's good mood.⦿ it's off | When an event of some kind is "off", that means it's BEEN CANCELED. ⦿ to deal with it | to accept a situation whether you like it or not⦿ there'll be no end to the [noun] | Used to predict that there will be an UNBEARABLE AMOUNT of something — usually, but not always, something negative or unpleasant.⦿ to come off like a/the [noun] | to BE REGARDED AS a [noun] by everyone because of your actions⦿ the bad guy | the person (man or woman!) who ruins everything, causes a problem; the villain in any given scenario or situation⦿ to tip someone off | to give someone secret or privileged information; Here: to FOREWARN someone about a surprise somebody has planned for them.

A teacher gives pointers and offers help with a difficult math assignment.

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Teacher: The problems in this chapter are a little complicated. I recommend you read through them several times. Now, if after reading it several times, you still don't understand, see me after class and I'll give you a study guide.

____________Here, the teacher uses Now, with a pause, to add a side note to what he just said. As such, it has a nuance of Having said that... Here, the general meaning is PAY CLOSE ATTENTION TO WHAT I'M GOING TO SAY NEXT.
⦿ to check in | To call or go see someone to CHECK ON THE STATUS or progress of a pending situation.⦿ package | A trip priced to include travel, accommodations, meals, tours, etc.⦿ isn't for you | isn't THE KIND OF THING YOU LIKE⦿ at your own expense | Here: you'll have to PAY FOR THEM YOURSELF because they're not included in the package rate.⦿ Sounds like a plan! | This phrase is commonly used when someone proposes an activity or a plan of action, and you WHOLEHEARTEDLY AGREE to it.

Nicky wants to take Natasha to Thailand for their anniversary. He calls his travel agent, Lynn, to check on the booking.

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Nicky: Hi Lynn! Just checking in. Did you find us a package for Thailand?

Lynn: I sure did. A one-week package in January. I'm booking you in at the group rate so you can save some money. 

Nicky: With a group? 

Lynn: Yes. That just means you have to fly there with a group and stay in the same hotel. They'll send you a program with scheduled tours, meals, etc. Now, once you're there, if you decide the group thing isn't for you, simply tell your guide you want to spend the day on your own or eat somewhere else and that'll be fine. But keep in mind that any meals you take away from the group are at your own expense.

Nicky: Sounds like a plan. Book it!

____________Here, Lynn explains the terms of the booking. Then she uses Now to let Nicky know that after having explained what's involved in a group booking, she's going to list the exceptions — the things he can do if he and Natasha don't want to be part of the tourist group and would rather do things on their own.