Grammar: Like / As

like = similar to He's an athlete, like his father.
such as = like Some sports, such as sky diving, are dangerous.
as = in the same way Do it as I've shown you.

Compare: He works as a teacher. (NOT: like a teacher) (He's a teacher.)
He works like a slave (NOT: as a slave) (He isn't a slave, but he works very hard.

Grammar: Present perfect simple (Affirmative & Negative).

Form: have/has + past participle

We use the present perfect for:

• actions which started in the past and continue to the present. They have been here since 2008.
• life experiences (time isn't started) I've tried Chinese food.
• actions that happened in the past and we can see their results in the present. She's broken her leg (When? We don't know, but we can see that her leg is in a cast.)

Note: When we use never in the negative we use have/has.

I have never eaten papaya. (NOT: I haven't never eaten papaya.)

Compare: He has gone to Madrid (He's still there).

                 He has been to Madrid (He's back now).

Superstitions in México

Mexican superstitions run as deep as the rich cultural and religious history of the nation. Superstition and religion both delve into the realm of the unknown, using tradition and faith to give creedence to customs and claims that can't be verified in practical ways. While religion sometimes keeps superstition at bay, superstition has its own way of twisting stories and truths in order to keep the public in awe of its power. 

One traditional superstition is that if a pregnant woman walks outside during a lunar eclipse, she runs the risk of giving birth to an infant who is part wolf or who has a cleft palate. 

Another common Mexican superstition has to do with the evil eye. Called "mal de ojo" in Spanish, the evil eye can cause all sorts of calamities to people and also to material items.

In reality, the evil eye can be condensed down to jealousy and desire. If a stranger looks upon your child or baby with either of these emotions in her eyes, she has just given your child the evil eye. To keep the evil eye at bay, whenever a person looks at a baby and offers a compliment, she must touch the child at the same time.

Other widespread superstitions include the following:

• Never walk beneath a ladder.
• Never cross a black cat's path.
• If you drop a tortilla, you will have lots of company.
• If you cut a baby's fingernails before the age of one year, the child will have impaired eyesight.
• Tuesday is unlucky; never start a journey or anything important on this day