我请客。
It will be my treat.
A: How about this...We make it a working lunch this afternoon.It will be my treat.
B: I like pizza.Let's make it a date for pizza and the selling account at 12:00.

订外卖
order some take'away food/food for delivery
A: Everyone,it's time for a break.You have been busy for the whole day,thank you.
B: It doesn't matter.We are used to it recently, we've been burying our heads in work since getting here.
A: I know you have been working very hard these days.We really had too much of a burden.
Well,I will order some food for delivery,it will be my treat.

留出更多时间吃午饭
leave/give sb.more time for a longer lunch
A: For our lunch meeting with the investors,
do we have to make a reservation at the restaurant or do we just show up?
B: To be on the safe side,I will order a table for 12 o'clock.
Will that suit your schedule?
A: Can you make the reservation a little earlier?
If we start earlier,it will give us more time for a longer lunch.

丰盛的午餐
a full'course/rich meal
A: Are you planning to treat the investors to a full'course meal?
B: Yes,we'll start with appetizers,follow with a soup and salad course,
then main dishes of prime rib or chicken cordon bleu,
and finish up with a delicious rich dessert of some sort.

地道的美味
It's really delicious!
A: The dish is called the sweet and sour fish.How do you like it?
B: It's really delicious!Better than that of the other restaurants.

别扯远了。
Let's not get carried away/too far
A: I believe the new look will make the customers notice them more,
and the high quality will keep them satisfied.
B: Maybe the ads company will also give us some surprise.
A: That will be great,but let's not get carried away.We'd better finish the dishes.

为合作干杯
(Let's drink) to our cooperation!
A: That's something rather special.I would like to have some more.
B: I'm glad you like it.Let's drink to our cooperation.

有意义的午餐
a productive/meaningful lunch
A: Well,that was a wonderful meal,thank you so much.
B: We're delighted that you joined us.It was a very productive lunch.

很高兴您能赏光。
I'm really glad you could come.
A: Thank you very much.Lunch was delicious.
B: Don't mention it.I am really glad you could come.