chichi ga unten dekinai hi wa, haha ga kuruma o untenshimasu.

On days when my father can’t drive, my mother drives the car.

Breakdown of chichi ga unten dekinai hi wa, haha ga kuruma o untenshimasu.

• は: topic particle
• 車くるま: car
• を: direct object particle
• が: subject particle

Questions & Answers about chichi ga unten dekinai hi wa, haha ga kuruma o untenshimasu.

What role does the first particle が play in 父が運転できない日?

In the subordinate clause 運転できない, 父が marks “father” as the subject—the one who cannot drive. In Japanese potential forms (～できる/できない), the subject is typically marked with が to emphasize ability or inability.

Why is there no particle between 運転できない and 日?

Japanese uses relative clauses without extra connectors. You directly stack the clause 運転できない (“cannot drive”) in front of 日 (“day”) to mean “the day when [someone] cannot drive.” There’s no need for a word like “when” or a relative pronoun.

What does 運転できない mean, and how is it formed?

• 運転する = “to drive.”
• To express ability, you use the potential form of する, which is できる.
• Thus 運転できる = “can drive,” and 運転できない = “cannot drive.”

Why is は used after 日?

The particle は marks 日 (“day”) as the topic of the main clause. It tells the listener: “As for the days when father can’t drive, …” This shifts focus to those days as the setting for what follows.

Why are が and を used in the second clause 母が車を運転します?