Against
“Against” puede funcionar como preposición o adverbio. A continuación analizamos su uso como preposición.
1.- Contra algo (apoyado sobre algo, presionando sobre algo, golpeando, rozando)
I lost control of my car and smashed against a tree
My father knocked his shoulder against a bar
My daughter fell against the fence
The path was so narrow that I brushed against the plants as I passed by
Put the bed against the wall
The policeman leaned the ladder against the tree to rescue the cat
He placed the cycle against the tree
2.- En la dirección contraria a un movimiento / una corriente
I got very tired swimming against the current
The sailing ship couldn’t move forward sailing against the wind
3.- En oposición, en contra o en desacuerdo con algo
My team won the match against an inferior opponent
The Prime Minister is pushing for elections against the opinion of his cabinet
The public opinion is against the war
4.- En contraste
The hut looks so small against the trees behind it
The polar bear is almost invisible against the snow