Some interesting Engpsh fixed phrases include:

"A piece of cake" - this means something is very easy to do
"Add fuel to the fire" - this means to make a bad situation worse
"Beat around the bush" - this means to avoid talking about something directly
"Bite off more than you can chew" - this means to take on more than you can handle

These are just a few examples, there are many more interesting fixed phrases in Engpsh!