1. yo nunca (tener) problemas en mis viajes.

1. Yo nunca _HE TENIDO_ (tener) problemas en mis viajes.

Explanation:

I have never had problems in my trips.

Tener is in infinitive, it means to have.

In this case you are refering to events in the past with continuity so you use the pretérito perfecto (past perfect) which is HE TENIDO.

That means that in the trips you have done over your life, there have not been any problems. The possibility of more trips in the future, and problems in them, is open.

the cinema would be a very good place to go.

this question is given using the conditional form. conditional tenses are is used when talking about hypothetical situations and probabilities. also, this is used when making polite requests. so comprarías is the conjugation of the verb comprar that matches the second person singular in the conditional. finally:

¿cuál comprarías tú?