Questions & Answers about Gözlerimi kapatmak zorundayım çünkü tren çok hızlı.
How do we form the "I have to" part in kapatmak zorundayım?
The structure for strong, external obligation uses the full infinitive verb (here, kapatmak) followed by the word zorunda. To show who has to do the action, you simply attach a personal "to be" suffix to it. Here, zorunda + -y- (buffer) + -ım (I am) gives us zorundayım.
What is the difference between saying kapatmak zorundayım and kapatmam lazım?
While both express a need to do something, zorunda is stronger. Words like lazım or gerekiyor generally mean "I need to" or "I should." Using zorunda implies an external obligation or that you have no other choice. In this sentence, the extreme speed of the train is physically forcing the speaker to close their eyes.
Why is there an -i at the very end of gözlerimi?
That is the accusative case suffix, which marks the specific direct object of the verb kapatmak (to close). The word breaks down as göz (eye) + -ler (plural) + -im (my) + -i (accusative). Whenever you are doing an action to a specific, possessed object like "my eyes", the accusative case is required.
Why doesn't the sentence end with hızlıdır to mean "is fast"?