•Chase rainbows/a rainbow (idiom) -

To pursue some goal or accomplishment that is utterly unrealistic or unlikely to happen.（做白日梦，异想天开）

Examples:　　

1.You can't chase rainbows your whole life - you need to pick a stable career and start being an adult.

2.It feels like the government is chasing a rainbow in its efforts to overhaul the tax legislation.

•Stop at nothing (idiom) -

Used to say that someone will do anything to achieve a goal or purpose, even if it is very bad.（不择手段，无所不用其极）

Examples:　　

1.They will stop at nothing to get him elected.　　

2."I assure you, ma'am, we will stop at nothing to catch that thief," the police officer said.

•Barefaced (adverb) –

Not show any shame about, or does not try to hide, bad behaviour. （露骨的，厚颜无耻的）

Examples:　　

1.How does he make so barefaced a lie appear to be a truth?

2.This is one of the most barefaced acts of historical rewriting ever.

•Throw one's weight about/around (idiom) -

If someone throws their weight around/about, they act aggressively and use their power over other people more than they need to.（耀武扬威，专横跋扈）

Examples:　　

1.The boss came in, yelling and generally throwing his weight about.　　

2.The PE teacher was a tyrant who threw his weight around when it came to punishing his students.

•Make an issue (out) of sth (idiom) -

To argue about something or insist that something be treated as an important problem even it is not.（拿…说事，拿…做文章）

Examples:　　

1.There's nothing wrong with your hair, so stop making an issue out of it.

2.I knew they'd made a mistake, but I was too tired to make an issue of it.