написать предложения на английском с идиомами :a piece of cake, bread and butter, selling like hot cakes, a bad egg, as cool as cucumber

Конечно! Вот несколько примеров предложений на английском с использованием указанных идиом:

1. A piece of cake
   The exam was very easy; I finished it in 10 minutes—really a piece of cake.

2. Bread and butter
   Teaching math is my bread and butter; I do it every day to earn a living.

3. Selling like hot cakes
   The new smartphone model is selling like hot cakes; everyone wants to buy it.

4. A bad egg
   We decided not to trust him because he’s known to be a bad egg and often causes trouble.

5. As cool as a cucumber
   Even during the surprise quiz, she remained as cool as a cucumber and answered all the questions confidently.

Если нужно, я могу подготовить ещё примеры или объяснить значение идиом!