Idiomatic expressions pose an exciting challenge to students because their individual words take on a new meaning when the expression is considered as a whole and what is more, some expressions are completely opaque (that is, obscure in meaning), even when the students know every word the idiom is made up of.
Taken from http://www.aperfectworld.org/metaphors.html
Beginning students try to understand everything literally. Firstly, show them we have idiomatic expressions in our own native language, but, since we use them unconsciously, we do not usually think about their constituents (of course, try to say that as naturally as possible). Let us take, for example, the idiom “sleep like a log” and its corresponding version in Portuguese (“dormir feito uma pedra”). We are perfectly aware that stones do not sleep, even so we think there is an element of comparison between sleeping and a stone’s inanimation. Show students that in English this association is quite similar (a log), making them aware that idioms are not always translated literally from one language to another.
Taken from http://www.luso-poemas.net/modules/news/article.php?storyid=267711
Another curious example in Portuguese is “cara de tacho” (= embarrassed). There is no such idiom in English, so we would need to find another way of expressing this idea (for example, “look like an idiot”). By the same token, remind your students that some idioms in English will not have a corresponding, direct counterpart in Portuguese. Unlike the first example (“sleep like a log”), in “cara de tacho” there is not any clear association.
Another way of helping students come to terms with learning idioms is to show them that in some cases we need to delve into the origin of the idiom. Actually, when we learn idioms in a natural, communicative setting, we assimilate them without even thinking about their origins. However, when we are learning a foreign language, sometimes idioms strike us as somewhat strange. If we do not have a corresponding idiom in our own language, it may be difficult for us to commit it to our memory.
Taken from http://www.idiomexamples.com/for/cry-idioms/
Let us take, for example, the idiom “cry wolf”, whose origin is as follows:
The origin of this phrase is believed to be from Aesop, a Greek fabulist who is said to have lived from 620 to 560 BCE. He wrote a number of different fables known collectively as Aesop’s Fables.
One of the stories credited to his name tells of a young boy who was given the responsibility of watching over some sheep for the night. The boy eventually grew bored with his assignment and thought it would be rather humorous if he pretended to be in danger, so he started shouting “wolf, wolf!” His plan worked, as the people nearby heard his cries for help and came rushing to lend their support, only to learn that it was all a silly ruse.
After this repeated a few more times, the people wisened up and no longer responded to the boy’s deceitful cries. Later on, a real wolf showed up, and now the boy seriously started to cry for help, but it was too late, because nobody would listen to him any longer.
Indeed, when someone constantly lies, they lose the trust of others. Thus, the phrase ‘crying wolf’ is thought to have originated from this story; it references the lying boy.
As can be seen, there is a complex explanation underlying the use of this idiom. Remind your students that even native speakers are unaware of the origins of the idioms they use. Raising foreign language students’ awareness towards the origin of the idiom may help them commit the idioms to memory by association.
Below are some interesting idioms whose origins may help you understand them and use them effectively:
cost an arm and a leg (“custar os olhos da cara”)
Taken from http://www.jantoo.com/cartoons/keywords/cost-an-arm-and-a-leg
As in Portuguese, would you pay for something by offering your eyes? Just make students analyze the meaning in their mother tongue and they will realize they recognize this idiom intuitively, without any need of a formal explanation. It is noteworthy to point out that it is not always possible to pinpoint the exact origin of an idiom.
Happy as a clam (“feliz como pinto no lixo”?)
Taken from https://caronessauthor.wordpress.com/2014/02/10/happy-as-a-clam/
This idiom means feeling very happy, elated. Why would clams be happy in the first place? When clams are at high tide, they cannot be caught by humans, unlike when the low is tide, when they can easily be dug out of the ground. The closest in meaning in Portuguese is “feliz como pinto no lixo”.
A chip off the old block (“é a cara do pai”)
Taken from http://bit.ly/28UbT78
Taken from http://bit.ly/28SM3QC
Sometimes an idiom is comprised of words that have several meanings (“chip”, for example, can refer to food or a computer part), but here it means “small piece”. The “old block” is someone’s father or mother. If you are “a chip off the old block”, you look like your parents, since you were made from the same material as them (they are the larger piece which you came from). This idiom shows us that, even though it is not always advisable to translate idioms, sometimes students may need to look up the exact meaning of the main word(s) that the idiom consists of.
Be on cloud nine (“estou no paraíso”)
Taken from http://blogadinhadosvirtuais.blogs.sapo.pt/cloud-9-190531
If you are “on cloud nine”, you are very happy and satisfied. This idiom is thought to have originated from meteorologists, who used to classify clouds and number them according to altitude. “Number nine cloud” are very high clouds, and if you’re lying comfortably on one of them, you are very in very high spirits.
Throw in the towel (“jogar a toalha”)
Taken from http://worshipministry.com/dont-throw-in-the-towel/
In boxing, throwing in a towel into the ring means that the fighter has already been defeated, and therefore that he has given up or surrendered. We have the same idiom in Portuguese and its use is exactly the same.
Needless to say, using pictures will greatly help make your English idioms classes more lively, after all, as we all know, “a picture is worth a thousand words”!
Taken from http://oels.byu.edu/student/idioms/proverbs/a_pic_thousand_words.html
Refresher Vocabulary & Grammar Tests For Advanced Proficiency Exams with Answers by Ricardo Madureira, Disal Editora.
For supplementary exercises (free of charge) (units 11 – 15), from my book “Refresher Vocabulary and Grammar tests…”, please go to: http://www.profricardomadureira.com.br , click on ARTIGOS and then download the file.