Idioms:

1-bite the hand that feeds you
to treat someone badly who has helped you in some way, often someone who has provided you with money
Leaving the company after they've spent three years training you up - it's a bit like biting the hand that feeds you.
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2-be in the same boat
to be in the same unpleasant situation as other people
She's always complaining that she doesn't have enough money, but we're all in the same boat.
If he loses his job he'll be in the same boat as any other unemployed person. [often + as]
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3-round of applause
when people clap:
The singer got a big round of applause.

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4-pick up the bill/tab (US ALSO pick up the check) INFORMAL
to pay for what has been bought, especially a meal in a restaurant

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5-pat sb on the back
to praise someone for doing something good

I got a pat on the back from (= was praised by) my boss.

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6-under your breath
quietly so that other people can not hear exactly what you are saying:
He muttered something under his breath.