Take care always!
The literal translation of that sentence is "Ten un viajo seguro" which is fine, but "Buen viaje" is more common. Both are correct.
Que tenga / tengan / tengas / tengáis buen día.Que pase / pasen / pases / paséis buen día.Que tenga un buen dia
This looks like a badly translated sentence from English to Spanish, probably from the English: "Have a nice nap." But you would never say "que tenga una buena dormir," which literally means "may you have a nice sleep." More likely in Spanish you would say simply "Duerme bien" which means "Sleep well."
Espero que tenga un buen dia
What does I will under the moon and the star if I have to do with stones
That means, "You can't always have what you want."
"Be more careful, because there's a chance that your parents read this."
tenga is the 1st person or 3rd person subjunctive form of tener [to have]. An example sentence using tenga is: Es importante que él tenga un gato. [it's important that he has a cat.]
The literal translation of that sentence is "Ten un viajo seguro" which is fine, but "Buen viaje" is more common. Both are correct.
Haga lo que tenga que hacer.
Because we always want that which we cannot have
Que tengas un lindo día Que tengas un bello día Formal or respectfully: Que tenga un lindo día Que tenga un bello día
Take good care of yourself. The subjunctive is used in this type of stement because it implies a wish or desire on the part of the speaker, not a statement of fact. Another common use of this form is "Que tenga un buen día", or "have a good day".
Que tengas un buen dia OR Que tengas buen dia = Both informal Que tenga un buen dia OR Que tenga buen dia = Both formal
As always I have much to tell/say
Hielo es siempre frio.
Que tenga / tengan / tengas / tengáis buen día.Que pase / pasen / pases / paséis buen día.Que tenga un buen dia