Every Saturday I’ll give you a couple of idioms to learn. An idiom is a saying or phrase whose meaning cannot be taken from the literal meanings of the words.
change horses in midstream: to make a change in plans or leadership during a critical moment
Example:
Originally we had planned to drive to California for summer vacation, but when our car broke down in Texas, we had to change horses in midstream, and ended up staying in Amarillo the whole time.
copycat: someone who imitates the actions or work of another.
Example:
Babies are natural copycats. They learn by imitating the behavior of others.